Lederberg still had a strong, alert stare, but his steps were feeble now. He used a walker to move around the desk and greet me. His beard and his gravity gave him a famously rabbinical look; he was descended from rabbis on both sides, and his mother could trace her family tree back through a long series of rabbis and rabbinical scholars all the way to Dov Ber, the Maggid of Mezritch-the Great Maggid, who led the Ha.s.sids of Eastern Europe in the eighteenth century.

"Did the Maggid live a long life?" I asked him.

"I have no idea," he said brusquely. "Elie Wiesel might know." Lederberg said he'd never thought much of the idea of glorifying one's heritage by tracing one's distant ancestors. "So we go back. After Methuselah, then what?"

We talked about the evolution of aging, and soon got into very deep water-or else very shallow water, because one realizes, in conversations like this, how shallow all our precepts and percepts may be.

"But exactly what is it that's being conserved, when you talk about immortality?" Lederberg asked at one point. "Do you want to freeze your ident.i.ty or are you willing to die a little bit to let innovation creep in?"

Some part of you dies every second, he said, as your neurons go one by one. And a certain number of neurons are also born every second. That's part of neuronal turnover. "And the whole corpus of our memories, our recollections, changes from instant to instant. If we could do it, exactly how much of that do we necessarily need to conserve?"

He gave me a long level stare. "In other words," he said, "how much immortality do you want?"

Chapter 12.

THE EVERLASTING YES AND NO.

Not long ago I had breakfast with Eric Roth, a Hollywood screenwriter who lives in a beach house in Malibu. He had just finished a screenplay about a character who is born old and grows younger and younger, living the seven ages of man in reverse. This screenplay was inspired by a short story, "The Curious Case of Benjamin b.u.t.ton," which F. Scott Fitzgerald published in Collier's Collier's magazine in 1922 and included in his book magazine in 1922 and included in his book Tales of the Jazz Age Tales of the Jazz Age. As a newborn, Benjamin looks seventy, the biblical three score years and ten, and his father calls him Methuselah. By the time he dies, Benjamin is a baby at last, as lost to the world as the very oldest old, sans everything.

Roth's house is built right on the edge of the Pacific. You walk out the back and down the stairs, and then you have to take off your shoes. After our bagels and coffee, I borrowed a pair of swimming trunks and went wading out alone into the ocean. Roth was already upstairs on the second floor tapping away at his computer keyboard, surfing the Web, fishing for his next project; but I had to go into the water.

The bottom dropped away in just a few steps. Almost instantly I was over my head.

"The test of a first-rate intelligence is the ability to hold two opposed ideas in the mind at the same time, and still retain the ability to function," Fitzgerald wrote in one of his notebooks. By that standard, mortality itself is beyond us. We still can't hold it in our heads, although we never get tired of trying. All our lives, we're astonished to find ourselves growing older.

Even as a civilization we are simpleminded. The dream of utopian science, the cure-all of cure-alls: that is one idea we hold in our heads. In Francis Bacon's fantasy of the New Atlantis, one of the first science-fiction stories, he describes a new foundation, "the n.o.blest foundation that ever was upon the earth," a company of brilliant minds exploring and discovering the way things are. "The end of our foundation," its spokesman declares, in Bacon's fantasy, "is the knowledge of causes and the secret motion of things; and the enlarging of the bounds of human empire, to the effecting of all things possible." Bacon hoped the brilliant sun of that New Atlantis would rise in the New World, and bring on the dawn of everlasting youth. We live by the light of that hope everywhere today, from East to West-as John Updike once put it, "our craven hope that science will save us."

When the sun shines, we dream of perfect knowledge, ageless bodies, utopian economics. The smartest people, the best and brightest, fall for fads that are, on the face of it, doomed. Eat More, Weigh Less Eat More, Weigh Less. The market will only go up. The rising tide will lift all boats, with the help of the invisible hand. Ever more. We know know. We mix spiritual and anatomical and financial advice, wisdom literature and medical literature. When we read in the Upanishads: "There are a hundred and one arteries leading to the heart; one of them pierces the crown of the head. He who goes upward through it, attains immortality," most of us are clear which magisterial realm we are swimming in. And yet we buy thousands of books that confuse our innate sense of direction; and when we try to find our way upward through them, we miss trouble down here below.

Dystopian science, the nightmare of absolute disaster: that is another idea we hold in our heads, but not at the same time.

The surge of our feelings around this problem of mortality is so simple and so repet.i.tious that our surprises of grief and delight are endlessly renewed, like incoming waves on outgoing waves. To hold two opposing thoughts in our heads is completely beyond us. But what makes us hope the world is absolutely perfectible, from the skin out and the skin in? And what makes us despair of all possibility of meaningful improvements? Why always one or the other? Why should our fate be any simpler than our physiology?

Back on land in Malibu, Roth told me how he'd adapted the story of Benjamin b.u.t.ton, and how Brad Pitt had signed on to play b.u.t.ton, and Cate Blanchett the love of his life; how the special-effects team had managed to show Pitt as a baby who is born with wrinkles but is rejuvenated with the pa.s.sage of time. When I told Roth what I was working on, he said it was obvious that biology would make us immortal soon, in another twenty or thirty years. I forget how many years he said. A cure for aging was so close and so settled a question that it wasn't even interesting. We have learned so much now that immortality is inevitable. Anyone who knows anything about the way science is accelerating has to feel that way. "Don't you you?" he asked. "Don't you you?"

For the Victorian critic and philosopher Thomas Carlyle, the two great contraries in life were spiritual: the "everlasting yea" and the "everlasting no." His great yes yes meant faith in G.o.d and all that is right, sacred, just, transcendentally good in the world. His meant faith in G.o.d and all that is right, sacred, just, transcendentally good in the world. His no no meant the h.e.l.l of evil, unbelief, all that is spiritually withered or dead. Our souls have to choose between that everlasting yes and no. meant the h.e.l.l of evil, unbelief, all that is spiritually withered or dead. Our souls have to choose between that everlasting yes and no.

For us-for my crowd, at least-when arguments turn cosmic, the great contraries in life tend to be material. We don't argue very often about our faith in an afterlife; but we do sometimes argue about the feasibility and desirability of another fifty years right here. And again the answers tend toward yes or no.

When you talk this way, you often hear yes and no from couples. Once, over a dinner in Princeton, I asked a distinguished writer and his wife if they would like that extra fifty years. She found the idea repulsive; he thought it would be delightful, as long as he could play with his grandchildren and ride his bicycle. He looked at her with tenderness that was oddly like an apology.

Eric Roth and his wife, Debra Greenfield, also voted yes and no. But he was a screenwriter with a movie about rejuvenation, and she was a lawyer who had just taken a degree in bioethics, so that may not be surprising.

The greatest extreme I've ever encountered was in the marriage of Aubrey and Adelaide. Like Aubrey, Adelaide wore simple old hippie clothes that had survived a lot of washings. Unlike him, she'd long ago lost every ounce of professional ambition. She had given up teaching and the rat race of publish or perish. When I first met her, she had just spent a year repeating someone else's failed experiment with a fly gene called scant scant, finding and fixing the mistakes, so that her colleague could publish the work. "I'm a good geneticist, but I have no career anymore," she told me with a smile. Most Americans take good care of their teeth, but she seemed to have let hers go, and most of them had gone. The few that were left were stained tobacco-brown.

She didn't seem to miss her tenure or her teeth. She sat at her tiny desk all day under her Gothic stone winding staircase and solved the eternal problems of scientists whose projects had hit glitches. While she worked, she chain-smoked Parliaments, Pall Malls, Marlboroughs, Camels, Lucky Strikes-anything without a filter.

Aubrey loved Adelaide very much, and it was one of the sorrows of his life that she had no interest in immortality. I often saw a softening of his hard pale face when he looked at her, a sort of warming of the alabaster. "I can't make progress talking with Adelaide," he told me sadly. He felt the most bitter frustration that he couldn't change her mind. "Whereas with others it doesn't upset me. It's their choice."

Aubrey had arranged to have his head frozen if he died prematurely, to be revived when the day of everlasting youth has dawned; and at night, over dinner, he was trying to coax her to do the same.

When it comes to our health, most of us find ways to resolve the everlasting yes and no. Whether or not we expect eternal life, or any little gift of extra time, we try to take care of ourselves.

"I am inclined to think," Descartes wrote to a friend, "that I am now farther from death than I ever was in my youth." He told a visitor, an English philosopher, that although he could not promise "to render a man immortal...he was quite sure it was possible to lengthen out his life span to equal that of the Patriarchs." In other words, a thousand years. And yet, when Descartes visited the young Blaise Pascal in Paris, in 1647, and found Pascal sick in bed, what did Descartes prescribe? Stay in bed, get lots of rest, drink soup. In principle, Descartes wrote in a letter, he could understand the body down to the last detail. "But for all that," he confessed, "I do not yet know enough to be able to heal even a fever."

Leonard P. Guarente, of MIT, who breeds Methuselah yeast and worms in his laboratory, takes a multivitamin when he gets home: "One of the ordinary, common ones. Also vitamin D. And a low-dose aspirin." He does not take resveratrol, the substance in red wine that the Guarente lab discovered, the drug that nurtures those yeasts in the petri dishes. Web sites are hawking resveratrol as a life-extension supplement now. The ads pop up everywhere, even next to a philosopher's essay on the acceptance of death, a priest's sermon on the afterlife, a careworn caregiver's blog about local hospice care: "Longevity on Sale. Relax. Take a deep breath. We have the answers you seek." Guarente says he will think of adding resveratrol to his daily pills, if and when the stuff is shown to work for us, and safe doses are established, and you can buy them in the drugstore. "Antioxidants, etcetera-none of it works," he tells his friends. "That's the best, the simplest thing to say. So far no drugs have demonstrated that you live longer. I defy you to name one."

What we do for our health does matter to our life span. Although genes are important-hence the wise old adage, "Choose your parents well"-behavior matters more. Studies of identical twins suggest that more than two-thirds of the variability in our life span depends on our environment; and environment, if we have any say in it, if we are free to make choices, is what we ourselves make of our lives. But generally what we should do is what we have known about for centuries. Listen carefully to the immortalists and then make yourself a good cup of soup. A long review article on the latest work in stem cells concludes: "The best advice is still to eat moderately and exercise moderately." Tom Kirkwood, reviewing Raymond Kurzweil's book Fantastic Voyage: Live Long Enough to Live Forever Fantastic Voyage: Live Long Enough to Live Forever, notes that most of its advice about health is sane, sensible, and very familiar. To enjoy the fantastic voyage into the future, stay with the tried and true.

The house where we lived during our summer in London, with the little garden in front and the wisteria that twined around the door as if to say, There will always be an England There will always be an England, was owned by an old friend of mine. He'd had a career as a publisher, and he was working on a novel, but he spent most of every day as a househusband. His life was a cross between our contemporary dream of fatherhood and the old dream of the English gentleman. His library was lined floor to ceiling with the world's great books, but also with the latest instructions on how to live forever. He ate well, he kept fit, he had a first-rate intelligence, but he also took dozens of antiaging pills every day, mail-ordered from Florida.

One morning he had a talk about aging with his youngest son, who was about to turn nine. He said we know enough now to live to the age of 120, at least. That day he planned to have lunch with an old friend who needed cheering up. He left the house at mid-morning and jogged to his gym. A few steps from the entrance, he fell down as if he'd been struck by a fist. It was a heart attack. An ambulance came within a few minutes, but he was dead.

Should we drink wine for our health? That's unclear. Should we drink red wine rather than white wine? That's unclear. Should we buy resveratrol? If you want to live long enough till medicine knows how to save you, stick with what medicine knows how to do well now. It's healthy to remember where we are in the scheme, in the immense journey of the caravan. Aubrey ends his book Ending Aging Ending Aging by saying, "Eat well, exercise, and support the Methuselah Foundation." He will look forward to shaking your hand someday in the distant future, with "the dark specter of the age plague driven away by the sunshine of perpetual youth." by saying, "Eat well, exercise, and support the Methuselah Foundation." He will look forward to shaking your hand someday in the distant future, with "the dark specter of the age plague driven away by the sunshine of perpetual youth."

That is fairly close to the health advice that Descartes gave Pascal.

Once after Aubrey and I visited Adelaide's nook, the three of us trooped up the narrow spiral stairway to the roof. Adelaide often nips up there for a smoke among the weather vanes of Cambridge: the c.o.c.k, the fish, the bronze cupola, exposed pipes, stone towers, and ugly tallish buildings that looked as if they were wrapped in aluminum foil for the freezer. She smokes by her rooftop garden, a few tiny clay pots. There we stood, the immortalist, the geneticist, and the journalist, admiring the same humble herbs that mortals have applied to the same problems for more than a thousand years: the leaves that may have done a little good, the sap that at least did no harm. "And this is aloe vera," said Adelaide, "a salve for my poor hands."

The field of gerontology is also divided between yes and no. Will aging be with us forever or not? Should gerontologists try to cure it, or just make our final years less awful? Are students of mortality poor cousins at the fringes of medical science, or are they working toward the salvation of the world, building the fountain of youth?

Gerontologists can't even agree if aging is a single unitary problem. Lederberg told me, "I'm still struggling to decide if there is a biology that can be called aging, that's different from what we call developmental biology on the one hand, and on the other-how shall I say this-simply the accidents of existence. If nothing else, the truck will run you over. With a certain probability. You can do statistics on that, and that's part of aging as well."

In other words, there are the accidents that strike our bodies from outside, and the accidents from inside-the accidents of metabolism. "Rusting," Lederberg said simply. If that is aging-if aging is nothing but the acc.u.mulation of all those accidents-then every medical program, from the pediatric to the geriatric, is a campaign against aging (and so is traffic safety). Current disputes in gerontology may come to seem less in the realm of the metaphysical and more in the realm of the methodological. We may see a reconciliation of the radical and the conservative gerontologists. Some of the field's leaders, including Robert Butler, the first and founding director of the U.S. National Inst.i.tute of Aging, who is now eighty-two years old, are talking about the goal of extending human life expectancy by seven years. One of the field's leading advocates, Dan Perry, argues that "the wellsprings of scientific knowledge capable of constructing new dimensions of life, health, and longevity are waiting to be tapped in the twenty-first century."

O Well of Gilgamesh!

Ana Maria Cuervo, the lysosome expert, collaborates with Dave Sulzer, a neuroscientist at Columbia. Cuervo and Sulzer are working on coaxing lysosomes to do better with the junk that causes neurodegenerative diseases. Sulzer says he and most medical researchers still feel it is more urgent to work on cures for specific diseases like schizophrenia, autism, Huntington's, and Parkinson's than to work on aging. That's the worldview they grew up with, he says. "Aging still seems more like the human condition. But will that last? Probably not." Essentially, regardless of the banner they work under, they are working on a cure for aging.

Jan Vijg, who is the chair of the department of genetics at the Albert Einstein School of Medicine and a respected name in gerontology, wonders why his colleagues are so adamant that we can't cure aging. "It's very shortsighted," Vijg says. When we study the problem of aging and seek to slow it down, to prevent the suffering of old age, we are doing what we intended science and medicine to do from the beginning, and what we want science and medicine to do for us every day of our lives. How different, then, is the one goal from the other?

In Vijg's view, we may be able to extend the human life span significantly and soon. There are so many flaws in our bodies, thanks to our evolution as disposable soma, flaws we may be able to fix through SENS-like interventions. Babies born in 2030 may have a life expectancy of 120 and live halfway into the next century.

Vijg complains about the world's pessimistic view of aging every time I see him. Just imagine what would happen, he says, if the people at the National Cancer Inst.i.tute were to announce, "We don't want to cure cancer, just make your last days more comfortable." They wouldn't get very far. But look, Vijg cries: that's just the way they talk at the National Inst.i.tute of Aging!

In Vijg's opinion, Aubrey got broadsided by the gerontologists because he was the first to declare war on aging, cogently and forth-rightly, in our present moment. That's why so many-particularly the older gerontologists-are furious with Aubrey, says Vijg. "He scooped them, in a sense."

Vijg wrote this to me the other day: "It's my impression that you have more difficulty than me in believing that we will really get there, and I am the scientist. I disagree with Aubrey on a lot of things, but I do think it's entirely rational to expect that we will be able to cure aging. While his ideas are often smart and he knows his stuff (I, like you, think he is quite brilliant), he lacks insight into the little things. And the little things in science are the reason I am now in 2009 about where I expected to be in 1989. He lacks insight into the hidden issues that often prevent projects from succeeding."

In Vijg's view, what will block our progress is the acc.u.mulation of mutations in our aging cells. In his recent book Aging and the Genome Aging and the Genome, Vijg argues that this load of mutations will be the wall we hit in the end. That will be "the ultimate limit to life," he writes. "Genomes cannot be cleansed of all genetic damage, because it is their nature to change and undergo mutation. Indeed, to keep genomes free of change would be to tamper with the logic of life itself."

Aubrey is not the only one who has tried to make an end run around this problem. The French novelist Michel Houellebecq imagines in his sardonic novel The Elementary Particles The Elementary Particles that a molecular biologist will soon discover a way to rewrite our genetic code into a form that does not mutate. The result will be a new species of clones who live forever in perfect tranquillity, without war, s.e.x, ident.i.ty, perversity, aging, or disease. that a molecular biologist will soon discover a way to rewrite our genetic code into a form that does not mutate. The result will be a new species of clones who live forever in perfect tranquillity, without war, s.e.x, ident.i.ty, perversity, aging, or disease.

That scenario amuses Vijg. He concludes his book, "I think most of us would prefer to live a bit shorter, with our imperfect selves and an aging genome."

Almost a thousand years ago a scholar of Chinese poetry, Ssu-ma Kuang, praised a line by the poet Li Ho, who had died a few centuries before him, in the year 817, at age twenty-six. The scholar wrote, "Li Ho's If heaven too had pa.s.sions even heaven would grow old If heaven too had pa.s.sions even heaven would grow old is a peerless line." The scholar also noted that a poet of his own day, Shi Yen-nien, had paid homage to that wonderful line with another, "which people think is a close rival to it": is a peerless line." The scholar also noted that a poet of his own day, Shi Yen-nien, had paid homage to that wonderful line with another, "which people think is a close rival to it": If the moon knew no yearning the moon would always be round If the moon knew no yearning the moon would always be round.

In the year 1760, a second scholar of Chinese poetry, w.a.n.g Ch'i, begged to disagree. "I have maturely considered the two lines; they exhibit the whole difference between the natural and the forced; there is no comparison between them."

The dews of Han are gone, along with the pans, the statues, the emperor, the dynasty, and the poets, but people still read those old lines and weigh them in the balance. That is as close to immortality as any mortal can come at present, as poets themselves eternally remind us. Theophile Gautier writes, "The G.o.ds themselves die out, but Poetry, stronger even than bronze, survives everything."

In a way it is a common gift, to conquer time within our mortal life. Lovers know this. They feel it solemnly: at once mortal and immortal. Couples experience it even in their very dailiness, in the choice endlessly renewed, the pledge freely given. In the very sacrifice, eternity, as strange as that sounds. Here we all swim in the same ocean, mortalists and immortalists. "Who knows this, daily enjoys the Kingdom of Heaven," as it is written in the Upanishads.

Aubrey's faith that we are all of us, all mortals on s.p.a.ceship Earth, in the middle of liftoff seems unshakable.

"Aubrey, come on come on!" I said to him the other day, when he was insisting to me once again that we can achieve escape velocity in our lifetime-that we are already blasting off.

"No 'come on,'" he said sternly. He wanted to know what made me think we couldn't do it. What made me so sure we weren't doing it now? He stared back at me as fiercely as a bearded pirate, not a flicker of doubt in his eyes. He looked absolutely unmovable. He is getting older now himself; there are silver threads among the brown, when the strong sun falls on his beard. The first wrinkles, the first age spots. He's had a parting of the ways with the Methuselah Foundation; now he runs the SENS Foundation. Immortality is the cause to which he has given his youth.

When this is all over, he told me, and someone has produced a way to rejuvenate a mouse, he is retiring to Madagascar.

"Madagascar?"

"I've had quite enough of this, I can a.s.sure you."

I remember when I first came across Aubrey's extraordinary name. I read a little squib about him on the Web-one of his first pieces of publicity. I sent him an e-mail, he wrote back more or less instantly, and soon there he was in my office chair, beer bottle in hand, telling me that we could live forever.

I warned Aubrey that I did not find his ideas completely kosher. I said it that day and many times thereafter. On the road to Ravenna he looked so much like Jesus, loping along, that I reminded him I wasn't a disciple, that he and I were not of the same faith. I quoted one of my father's Yiddish proverbs. "Az mih esst chazer, luzz rinnen ueber dem boord!" "Az mih esst chazer, luzz rinnen ueber dem boord!" If you're going to eat pork, let it dribble over your beard. If you're going to eat pork, let it dribble over your beard.

That's why I was talking with him and not with a conventional gerontologist, I said.

Aubrey laughed. "In for a penny, in for a pound," he said. "Jolly good."

Aubrey said I was crazy to doubt him-either crazy, or a lightweight. Sometimes at the Eagle the very sight of me seemed to exasperate him as I sat there smiling in my strained, coffee-stained sobriety. "It's just bizarre!" he would cry, like a lawyer at the bench, with a somewhat practiced indignation, his hands flying upward and his voice rising half an octave. "It's brainwashing! What other explanation is is there?" there?"

Meanwhile, from a stool at the far end of the bar, that old Cambridge codger kept staring at our table, the man with the fixed leer from the Mad Hatter's tea party, as if to say: You fools will never make sense. Whatever it is you are talking about, you will never make sense.

I still do not expect to see our last night's day, that dawn when immortality shall be unveiled, to the cry of the peac.o.c.ks. I think our last talk in the Eagle was the moment when that was settled between us.

"I know a lot more about biology than you do," Aubrey declared, very stiffly, with the late afternoon sun casting those apocalyptic shafts of light onto his face. "So any conclusions based on that a.s.sumption are just illogical. You're preferring your own uninformed speculations as a nonbiologist to mine."

And yet, now that the journey is over, I'm surprised to find myself wavering. Maybe I'm half of the devil's party without knowing it.

One of my best memories of Aubrey is the brief walk we took after we had paid and left the pub, debating on the cobbles and old flagstones. Aubrey showed me Trinity Hall, where he went to school, where he learned to punt, and where the ladder that led down to the river used to lean. He apologized for being so hard on me back at the Eagle. We agreed to disagree. He walked me partway to the train station through the English summer drizzle.

"Best of luck."

After we said our goodbyes, Aubrey sprinted off. He was late for dinner with Adelaide; he'd promised to be back at seven. He flew home down that old stone street like a schoolboy of twelve.

Notes on Sources and Further Reading "The subject is really an enormous subject," William James wrote in 1898, in his essay "Human Immortality." "At the back of Mr. Alger's Critical History of the Doctrine of a Future Life Critical History of the Doctrine of a Future Life there is a bibliography of more than five thousand t.i.tles of books in which it is treated." there is a bibliography of more than five thousand t.i.tles of books in which it is treated."

On top of that enormous subject, we now have the modern science of longevity. If you search for the keyword "gerontology" in the world's largest online index of medical literature, Medline, you get a list of more than 25,000 articles, all published since the year 1950.

Of course, longevity and immortality are not the same thing. Even if gerontologists learned to slow, stop, or even reverse the process of aging, they would not make human bodies live forever. They would eliminate only one cause of death. Nevertheless, aging is by far the most common cause of death in this vale of tears. A cure for aging would mean so many centuries or millennia of future life that the prospect looks very much like immortality from here.

Because the science of longevity is so young and turbulent, it's too soon for critical histories and giant bibliographies. Here are a few notes on some of my sources, chapter by chapter, with suggestions for further reading.

CHAPTER 1: IMMORTAL LONGINGS.

In the last decade or so, as their field has heated up, gerontologists have published a whole shelf of books for a general audience. These include: Austad, S. N. (1999). Why We Age: What Science Is Discovering About the Body's Journey Through Life. Why We Age: What Science Is Discovering About the Body's Journey Through Life. Wiley. Wiley.

Butler, R. N. (2008). The Longevity Revolution: The Benefits and Challenges of Living a Long Life. The Longevity Revolution: The Benefits and Challenges of Living a Long Life. PublicAffairs. PublicAffairs.

Carnes, B. A., and S. J. Olshansky (2002). The Quest for Immortality: Science at the Frontiers of Aging The Quest for Immortality: Science at the Frontiers of Aging. Norton.

Guarente, L. (2002). Ageless Quest: One Scientist's Search for the Genes That Prolong Youth Ageless Quest: One Scientist's Search for the Genes That Prolong Youth. Cold Spring Harbor Laboratory Press.

Hayflick, L. (1994). How and Why We Age. How and Why We Age. Ballantine. Ballantine.

Kirkwood, T. (1999). Time of Our Lives: The Science of Human Aging Time of Our Lives: The Science of Human Aging. Oxford University Press.

Rose, M. R. (2005). The Long Tomorrow: How Advances in Evolutionary Biology Can Help Us Postpone Aging The Long Tomorrow: How Advances in Evolutionary Biology Can Help Us Postpone Aging. Oxford University Press.

West, M. (2003). The Immortal Cell: One Scientist's Quest to Solve the Mystery of Human Aging The Immortal Cell: One Scientist's Quest to Solve the Mystery of Human Aging. Doubleday.