A door thudded closed above his head, and Pierce looked up. Rosie's feet crossed and then recrossed the floor above. Prying. Pierce riffled a little farther through the soft stack of sheets; he found chapter one. Once, the world was not as it has since become, it had a different history and a different future, and the laws that governed it were different too.

At the bottom of this page was a name and a date he knew.

A past moment of his child-being returned to him, when, where, the kind of soft surge of nameless body-memory that can be caused by a smell or a sound. He drew out Fellowes Kraft's hard chair and sat in it; he put his elbow on the desk and his cheek in his hand, and began to read.

Five.

Once, the world was not as it has since become.

It once worked in a different way than it does now; it had a different history and a different future. Its very flesh and bones, the physical laws that governed it, were other than the ones we know.

Whenever the world turns from what it has been into what it will be, and thus earns a different past and a different future, there is a brief moment when every possible kind of universe, all possible extensions of Being in space and time, are poised on the threshold of becoming, before all but one pass into nonexistence again; and the world is as it is and not as it was, and everyone in it forgets that it could ever be or has ever been other than the way it is now.

And just as the world is thus turning from the what-has-been into the what-is-to-be, and all possibilities are just for a moment alight and one has not yet been chosen, then all the other similar disjunctures in time (for there have been several) can become visible too: like the switchbacks on a rising mountain road suddenly becoming visible to a climber just at the moment when his car swings far out on the apex of the turn he is taking, and he sees where he has come from: and sees a blue sedan far down there climbing too.

This is the story of one such moment, and about those men and women and others who recognized it.

They are all now dead, or asleep, or do not figure in the history which the world has come to have; and their moment appears quite otherwise to us than it did to them. Today I pick up a book, a history of those times, and what it tells me doesn't surprise me; however these people misconceived their world (and apparently they misconceived it wildly, peopling it with gods and monsters, with non-existent lands having imaginary histories, with metals and plants and animals ditto, having powers ditto), they really dwelt in the same world I dwell in: it had these animals and plants which I know, this sun and these stars, and not other ones.

And yet, in the interstices of such a history book, between the pages, I discern the shadow of another story and another world, symmetrical to it, and yet as different from it as dream is from waking.

This world; this story.

In the year 1564, a young Neapolitan of the ancient town of Nola, making the great mistake of his life, entered the Dominican monastery of San Domenico Maggiore in Naples. It wasn't, of course, entirely his decision; his father was a retired soldier, landless and not rich, and the boy was brilliant (so the parish priest said) and a little wild, so there was really nothing for him but the Church. Still, the Dominicans, though the great and powerful order of the Kingdom of Naples, were not the order for this boy. Perhaps, if he had joined some smaller, less potent order, some hardworking Minorite or easygoing Benedictine or even cloistered Capuchin monastery, he might have been left alone to dream his dreams. If he had made his way into the Company of Jesus, they would have found some way to turn his pride and his strange gifts and even his distaste for Christianity to their own ends; the Company was well able to do that.

But the Dominicans: the order of Preacher-Friars, whose self-appointed mission was to keep pure the Church and the Church's doctrines; the Dominicans, who punningly called themselves Domini canes , the running dogs of the Lord, black-and-white hounds eager to bring down heresy like prey: that was not the order in which to incarcerate young Filippo Bruno, given the name Giordano when he put on his robe of black and white. The order didn't encourage independent thinking; it would never forgive the Nolan boy for turning his back on them, and carrying his heresies into the world; and in the end they would have him forever for their own, tied to a stake in Rome.

But there, for the moment, he is, in the monastery of San Domenico, going slowly up the right-hand aisle of the monastery church, avoiding the loiterers and the bravos and interrupting assignations. He stops at each side chapel, each statue niche, each architectural division, and stands before it long in thought before passing on to the next. What is he up to?

He is memorizing the church of San Domenico, piece by piece, for use as an interior storehouse or filing cabinet for remembering other things.

A hundred years before, books had begun to be made by the new ars artificialiter scribendi , the art of writing artificially, printing. Thousands of books have already been printed. But in the great monasteries of the Dominicans the age of the scribe, the age of the manuscript, the age of memory, is not over.

Printed handbooks on how to preach sermons are appearing, printed breviaries and books of homilies and Scripture quotations for priests to use, but the order of Preacher-Friars is still inducting its novices into the mysteries of memory arts as old as thought.

Take a large and complex public space-a church, for instance-and commit it to memory, every side altar, chapel, statue niche, and arch. Mark every fifth such space, in your imagination, with a hand; mark every tenth space with an X. Now your memory house is prepared. To use it, say to remember the contents of a sermon you are to give, or a manuscript of canon law, or a confessor's manual of sins and their appropriate punishments, you must cast vivid images in your imagination to represent the different ideas you wish to remember. Aristotle says clearly, and St. Thomas follows him, that corporeal similitudes excite the memory more easily than the naked notions themselves. If your sermon then is the Seven Deadly Sins, cast them as evil ugly characters, displaying appropriate signs of their qualities (from Envy's mouth a loathsome viper protrudes instead of a tongue; Anger's eyes flame red and he is brutally armed). Then have your characters stand in their places in order around the church or city square or palace you have in memory, and as you speak each one in turn will prompt you, Now speak of me, Now speak of me.

This was how the Scholastics had expanded and elaborated a rhetorician's trick mentioned briefly by Cicero and Quintillian; and by the time Brother Giordano was committing the church of San Domenico to memory not even its endlessly exfoliating spaces were sufficient to hold what he was given to remember.

Patristics, moral theology, summulae logicales , hagiography, the contents of compendia, encyclopaedias and bestiaries, the same tale in a thousand guises-the monkish passion for collection, dissection, division, and multiplication of notions filled the cathedrals of memory to overflowing just as those of stone were filled with gargoyles, saints of glass, passions, fonts, tombs, and judgments.

And as the amount to be remembered grew, so the means to remember it by expanded, divided, multiplied. Brother Giordano committed endless new rules of memory to memory. He memorized a system for remembering, not just notions and ideas, but the very words of the text, by substituting other words for them: so that the mental image of a city ( Roma) reminds the speaker to speak next of love ( amor). More: there were rules for remembering, not the words, but the letters of the words, an image for each, some corporeal similitude, so that the word Nola was formed in the Nolan's mind by an arch, a millstone, a hoe, and a pair of compasses, and the word indivisibilitate by a whole atticful of junk.

Giordano found he could do such tricks with ease; he composed a bird alphabet of his own, anser the goose for A, bubo the owl for B, and so on, and practiced with it until he could make In principio erat Verbum flutter and settle on his shoulders like a flock. The only difficulty he had was in expelling what he had once put in place, and ridding the church of San Domenico Maggiore of its birds, hoes, shovels, ladders, allegorical figures with snakes for tongues, gesturing captains, anchors, swords, saints, and beasts.

-Is it lawful then, when you have no more places left to fill, to make in imagination further places attached to those places?

-It is, Frater Jordanus, if you do it correctly. You must imagine a line running from west to east, upon which you are to place imaginary towers to use as memory places. The towers are multiplied, as many as you like, by being changed, turned this way and that way through their faces, per sursum , deorsum , anteorsum , dextrorsum , sinistrorsum . . . . The brother instructor's hands turned and twisted an imaginary tower.

-Yes, said Giordano. Yes.

-Now, said the brother instructor, raising a finger: you are only to use such towers to exercise and strengthen the memory. Do you hear? Not to use in remembering. Do you hear, Frater Jordanus?

But a line of imaginary towers had already begun to spring up, stretching west from the door of San Domenico: towers very much like the ones that Brother Giordano remembered from his Nolan childhood. Every year in Nola, to honor the city's patron St. Paulinus on his feast day, the various guilds of the town built and displayed tall towers made of wood and lathe and canvas, called guglie : multistoried constructions balconied and steepled, pierced with windows and openings large and small displaying scenes out of the saint's life, or of the Passion, or scenes out of romances or the life of the Virgin. Inside and out they were painted, encrusted with cherubs, roses, stars, zodiacs, emblems, exhortations, crosses and rosaries, dogs and cats. On St. Paulinus's day the guglie were revealed to the town, and then-most marvelous of all-each guglia was lifted up by thirty strong young men, and not only carried through the thronged and decorated streets, but, in the square before the church, was made to dance. The boys who carried them, grunting and crying encouragement to each other, made them bow, tilt, turn round and round to music: dancing with each other amid the people who danced around them, their crazy contents appearing in window and door and disappearing again as the towers turned and twirled, left, right, bowing, tilting, per sursum , deorsum , dextrorsum , sinistrorsum .

And yet: he would think-looking out the narrow window of his cell at a pale strip of evening, one star alight-that even an infinite line of guglie running east to west and changed every which way would not be enough to hold all that he had seen and thought of in his short life, which to him seemed so endlessly long as to be without a beginning at all. Not every leaf whose shadow had crossed him, not every grape that he had crushed against his palate; not every stone, every voice, star, dog, rose. Only by committing to memory the entire universe, and casting on it a universe of images, could all the things in the universe be remembered.

-Is it lawful to use the spaces of the heavens, I mean the zodiac and its houses, the mansions of the moon, for the purposes of remembering? And the images of the stars for images to remember things by?

-It is not lawful, Frater Jordanus.

-But Cicero in his Second Rhetoric says that in ancient times . . .

-It is not lawful, Frater Jordanus. To stretch and exercise the memory by artifice is a good work; to seek for aid in the stars is not for the likes of you. You understand neither Cicero nor the stars. And for that but you will be a long time on your knees.

As well as learning to write inwardly with images in the way the Dominicans were famous for, Brother Giordano also learned to write with pen and ink; to write in a thick quick secretary hand a monkish Latin untouched by umanismo , a Latin learned from the books he was given to read. He read Albertus Magnus and he read St. Thomas, the great learned doctors of his order; he overlaid his own inward cathedral with the cathedral, divided into apse nave and choir, parts and parts of parts, of Thomas's Summa theologica . Through Thomas he came to him whom Thomas had called simply the Philosopher, Aristotle. Aristotle: a mass of manuscripts greasy from use, copied and recopied, glossed and interpolated, grown blurred from the accretion of tiny errors.

All things seek their proper spheres. What is heavy, as stones and earth, seeks the center of the universe, which is heaviest; lighter things, as air and fire, leap upward to their spheres, which are lighter.

The inmost heaviest sphere is earth, and next to it the sphere of water, ascending as dew, descending as rain. The spheres of air and fire are next, and then the sphere of the moon. All change, all decay and corruption, all birth and death, occur in the spheres of the elements, below the sphere of the moon; beyond the moon are the changeless regions. That which suffers no change is more perfect than that which is subject to change; the planets are perfect matter, unlike any we know, attached to perfect crystal spheres, which, turning, mark time. These seven spheres are contained within an eighth, the crystal sphere wherein the stars are set. And that is contained within the utmost sphere of all, the sphere that, turning, turns all the others: the Primum Mobile, itself turned by the finger of God. For nothing moves except what is moved by a mover.

Cheek in hand, amid the nodding brothers in the library, Brother Giordano assembled within himself Aristotle's heavens and earth, like a man building a ship in a bottle. Time is thought to be movement of the Sphere viz. because the movements are measured by this, and time by this movement. What?

The brothers around him muttered aloud reading their books, a dozen voices reading a dozen texts, buzzing like stupid wasps. This also explains the common saying that human affairs form a circle, and that there is a circle in all other things that have a natural movement and coming into being and passing away.

He sighed, an ashen taste in his mind like the burnt summer day's. Why is changelessness better than change? Life is change, and life is better than death. This world of perfect spheres was like the world that painters show, where they pretend that some few leagues above the mountains a moon like a melon and stars like sparks go by, and just above them God bends down across the spheres to peek inside. It was a universe too small, made of too little; an empty trunk, bound in iron straps.

But there were other books.

Like many monkish libraries, San Domenico's was a midden of a thousand years' writing; no one knew all that the monastery contained, or what had become of all that the monks had copied, bought, written, commented on, given away, and collected over centuries. The old librarian, Fra' Benedetto, had a long catalogue in his head, which he could remember because he had composed it in rhyme, but there were books that weren't in this catalogue because they didn't rhyme. There was a Memory Palace in which all the categories of books and all the subdivisions of those categories had places, but it had long ago filled up and been shuttered and abandoned. There was a written catalogue too, into which every book was entered as it was acquired, and if you happened to know when a book was acquired, you might find it there. Unless, that is, it had been bound with another, or several others; for usually only the incipit of the first would be put into the catalogue. The others were lost.

So within the library which Fra' Benedetto and the prior and the abbot knew about there had grown up another library, a library which those who read in it did not catalogue, and did not want catalogued. Fra'

Benedetto knew he had the Summa theologiae of Albertus Magnus and his book On Sleeping and Being Awake ; he didn't know he had Albertus's Book of Secrets or his treatise on alchemy. But Fra'

Giordano knew. Fra' Benedetto knew he had the Sphere of Sacrobosco, for every institution of learning had the Sphere of Sacrobosco, it was the universal textbook of Aristotelian astronomy. He had several copies, and some printed texts as well. He did not know that bound up with one manuscript was the Commentary on the Sphere by Cecco of Ascoli, he whom the Church had burned at the stake for heresy two hundred years before.

He didn't know it, but Fra' Giordano did. Fra' Giordano read Cecco's commentary shut up in the privy, swallowing it like sweetened wine. The stars alter the four elements, and through the elements our bodies are altered, and through our bodies our souls: in the stars are the Reasons of the World, and Jesus's own horoscope was set at his birth by God so that he would suffer the fate that he did. Under certain constellations and conjunctions happy divine men are born, Moses, Simon Magus, Merlin, Hermes the Thrice-great (Giordano read this assortment of names with a deep thrill of wonder, that they could be listed together, as people of the same kind). Countless spirits good and evil fill up the heavens, constantly in motion, criss-crossing the zodiac; founders of new religions are actually born of them, of incubi and succubi who live in the colures, the bands that separate solstice and equinox.

Those perfect spheres were coming to contain a busy populace.

In the library, Brother Giordano read the books that a doctor of theology must read; he read the Fathers, he read Jerome and Ambrose and Augustine and Aquinas. He chewed and swallowed them like a goat eating paper, and excreted them in examenes and recitationes .

In the privy he read Cecco. He read Solomon's book on the Shadows of Ideas. He read Marsilio Ficino, De vita coelitis comparanda , on drawing down the life of heaven by talismans and incantations.

The privy was the secret library of San Domenico; there the books were read, and changed hands; there they were hidden; there they were traded in for others. Giordano was its librarian. He knew and remembered every book, where it lay in Fra' Benedetto's cases, who had asked for it, and what was in it. In his vast and growing memory palace, the whole heavens in small, all that took up next to no room at all.

His brothers marveled at Giordano's memory, and whispered how he had come by it. Giordano let them whisper. Addicted to gossip and sausages, they would never dare to put the stars to use: but Giordano dared.

Meanwhile the enormous sun burned in the blue, blue sky; pleasure craft and oared warships skimmed across the bay, the azure bay prinked with silver points of wavelets. The Spanish viceroy (for the Kingdom of Naples was a possession of the Spanish crown) rode through the city dressed in Spanish black, in his little black chaise; if he met the Host being carried through the streets to someone ill or dying, he would get down and join the procession, following it humbly to its destination. Every year the congealed blood of St. Januarius kept in the cathedral melted and flowed on his feast day as though just shed, and the people and the priests and the cardinal and the viceroy wept and groaned aloud or held their breaths in awe. Some years, the blood was slow in melting, and the mass of people pressed into the cathedral grew restive, and a riot would start to seethe.

There were always riots; there were always the poor, crowded in the tall close houses of the port quarters, in narrow alleys piled with refuse, where children grew like weeds, untended and wild and numerous. They begged with persistence, robbed with skill; they laughed equally at the pulcinelle in their booths around the Piazza del Castello and at the extravagant farewells of a brigand about to be hanged in the Piazza del Mercato. All day the naked beggars lay on the quays; at night, fisher-girls danced the tarantella on the flat roofs of cottages that ringed the bay under the moon.

The moon drew humid tears from the earth, attracting them upward by her own watery nature; by her action also, in the mud-flats of river estuaries and in sea-pools, frogs and crabs and snails were generated. When she was full, dogs all over the city turned their faces up to hers, and howled. When their own star Sirius arose with the sun, they went mad, and the dog-killers went out to catch them.

In the wood of dead trees, in the guts of dead dogs, worms were generated; from the guts of dead lions, bees were born-so it was said, though few had ever seen a dead lion. Horsehairs fallen in a horse-trough turned into snakes, and now and then you could see one starting: one hair beginning to whip sinuously amid the floating still ones. The sun shone, and the heliotrope in the gardens of the Pizzofalcone turned their faces to it, and the living lion in the viceroy's menagerie roared in his strength and pride. The moon drew the fogs, the sun drew the heliotrope; the lodestone drew iron, and Saturn in the ascendant tugged terribly at the brain of the melancholic man.

It was all alive, all alive, from the bottom of the sea through the air to the heavens, the stars altering the four elements, the elements the body, the body the soul. Brother Giordano sang his first Mass in Campagna, at the church of San Bartolomeo, whispering Hoc est enim corpus meum over the circle of bread he held in his anointed fingers, and in the warmth of his breath it was alive too. The heretics of the North said it was not alive, but of course it was; swallowed, it warmed Giordano's bosom with the small fire of its aliveness. Of course it was alive: for there was nothing that was not.

So the Nolan grew from boy into man, priest, and doctor; so the stars turned over the changeful world; so the memory he had made grew full of treasure, too full for reckoning, yet all of it his. Brother Giordano amazed his brothers, filling the evenings in Chapter after supper with feats that seemed more than human.

He had them read out lines of Dante chosen at random, here, there, in any canto; and then the next night he would recite them all, in the order they had been given to him, or backward, or starting from the middle. He asked them to name humble objects, fruits, tools, animals, articles of dress; over months and years the list grew hundreds and hundreds of items long, yet he could remember it all, or any part of it, in any order, starting anywhere: the brothers (who had them all written down) would follow along the lists as Giordano, hands folded in his lap, eyes slightly crossed, named each thing, seeming almost to taste it, to relish it, even as he took it from the hand of the kindly one who leaned from his tower window to proffer it: hoe, shovel, compasses; dog, rose, stone.

His fame spread. Among the Dominicans, at first, who were proud of the ancient art which they were well known for preserving and practicing; but then in the world at large as well. Giordano came to the attention of the Academia secretorum naturae , the School of Nature's Secrets, and of the great magician of Naples who presided there: Giambattista della Porta.

When he was only fifteen years old, this Della Porta had published a huge encyclopaedia of natural magic; then there had been trouble with the Church, and the young mage had come under the eye of Paul IV, and might very well have ended badly; he was exonerated at length, but now he kept his gaze firmly below the moon's sphere, and practiced only the whitest of white magics-and heard Mass daily, just in case.

He was an ugly, dog-faced, egg-headed man, swarthy and brutal-looking; at his temple a thick vein beat. As though in compensation, his voice was gentle and melodious, and his manners exquisite. With great kindness he led the young monk, defensive and rigid with unease, through the public rooms of the Academy decorated with allegories of the sciences and into an inner chamber where, at dinner, the fellows reclined in the antique style, wearing white robes and vine leaves in their hair.

They didn't giggle, or stare slack-jawed at him when he performed his feats; they considered, and asked questions, and put hard tests to him. One had made a list of long nonsense-words almost identical but not quite- veriami, veriavi ; vemivari ; amiava -thirty or more of them. Giordano broke them into parts, and for each part he found some visual clue: birds ( avi), lovers ( ami), a book of truths ( veri), a bunch of twigs ( rami). Then, hands folded in his lap and his eyes with that far-off cast in them (for they watched the scenes he had made out of the clues pass in his inward sight), he gave them all, and again, and differently. A girl gave her lover a white pigeon, in a cage made of sticks, and he sold it for a book. It happened in the piazza before the church in Nola, in scorched August; he could see the girl's shy look, smell the cracked leather of the book, feel the bird's quick heartbeat beneath his fingers: years later he would sometimes dream of these figures and their dramas, the girl, the bird, the boy, the book, the sticks.

He did all that they asked him, and more that they hadn't asked him-smiling at last, and leaning forward to see their amazement-and later when the guests were gone and he sat alone over wine with the ugly magician, he talked about how he did what he did.

-Places, and images cast on them, yes, Della Porta said, who had written a little Ars reminiscendi himself which included all the usual rules.

-Yes, said Fra' Giordano. The church of San Domenico Maggiore and the cloisters and the square before it. But it's not enough.

-Imaginary places can be used.

-Yes. I do.

-And images can be taken for use on them from our painters. From Michelangelo. Raffaello. The divine ones. Images of good and evil, strength, virtue, passion. These vivify the imagination.

Fra' Giordano said nothing, who had not seen their paintings, though the names seemed to make paintings in his mind, and he found a wall there to put them on.

-I use the stars, he said. The twelve houses. And their denizens. Those are powerful aids.

Della Porta's eyes narrowed.

-That might be lawful, he said carefully.

-But they're not enough, Giordano said. Even now the figures sometimes grow confused to me. Too few to do so much, play so many parts. Like a comedy with too few actors, and the same ones come on again and again in different cloaks and wigs.

-You may use the images of AEgypt, Della Porta said, clutching his knee in his hairy hands and casting his eyes upward. Hieroglyphs.

-Hieroglyphs . . .

-That is lawful. That much is lawful.

The monk was staring at him so fixedly that Della Porta felt compelled to go on.

-You see, he said, in their wisdom the AEgyptians made multiform images, a man with a dog's head, a baboon with wings. They were not so foolish as to worship such monstrosities. No. They concealed in their images truths for the wise to uncover. The baboon is Man, the Ape of Nature, who reproduces Nature's effects by imitation, but whose wings take him above the material plane as his mind pierces through appearances.

The monk said nothing, only still stared.

-A fly, said Della Porta. It means Impudence, because no matter how often it is driven away, it always returns. You see? And out of these images, linked, they made a language. A language not of words but of corporeal similitudes. Like your memory images. You see? In that book of Horapollo's there are seven dozen of them explained. Hieroglyphs.

The library of San Domenico did not have a book by Horapollo, or Fra' Giordano did not know of it.

He felt-he had felt since Della Porta had begun speaking of hieroglyphs-a weird hunger at the bottom of his being.

-What other books? he asked.

The mage withdrew slightly from the monk, who leaned toward him with an intensity Della Porta disliked.

-Read Hermes, he said. Hermes who gave to AEgypt her laws and letters. It grows late, my young friend.

-Marsilio Ficino, said Giordano. He translated the works of that Hermes.

-Yes.

-Marsilio knew images too. Was he taught by Hermes? Images of the stars, to draw down their power.

-That is not lawful, the mage said, standing suddenly.

-He made them in his mind only.

-It is not lawful and it is not safe, the mage said, lifting Fra' Giordano by a hand on his shoulder, and propelling him toward the door of the chamber.

-But, said Giordano.

-Your memory is God's gift, said Della Porta, almost a whisper into the monk's ear as, arm linked in his, he walked him to the street door. Your memory is God's gift and you have improved it wonderfully.

By natural art. Be content.

-But the stars, Giordano said. Cecco says . . .

Two servants had pulled open the double doors onto the piazza. Della Porta pushed Giordano out.