I SENSED HIM BEFORE I HEARD HIM. SEVERAL seconds pa.s.sed. I kept waiting for him to announce himself, but he didn't. Finally I turned and saw Thorpe standing in the doorway, watching me. He was wearing a white cable-knit sweater, linen slacks, and leather sandals. His head had been shaved clean, and he smelled of aftershave-a combination of orange blossom, musk, and leather, with a hint of patchouli and tonka bean. The fragrance was familiar, but I couldn't trace it to a particular person or time.

I had witnessed the third transformation of Thorpe in as many days. He looked nothing like the man who had answered the door a half hour before. His demeanor had changed as well. He had a bit of swagger now. The total effect of the clothes, the aftershave, the smooth and gleaming head, was of a man who'd come to take me out to Sunday brunch in Marin.

He walked into the room and looked out the window, down the hill toward my house. For a moment we stood side by side in the darkness. His arm brushed mine, and I moved away from him.

"Bulb's burnt," he said. "Wait here."

In a couple of minutes Thorpe returned. He stood on a chair to remove the light fixture, and handed me the old bulb. I shoved it into the overflowing wastepaper basket and wiped the greasy dust on my jeans.

"How many Marxists does it take to screw in a lightbulb?" he asked, as the new bulb flickered to life.

"I give up."

"None. The lightbulb already contains the seeds of its own revolution."

"Not bad."

He stood in front of me, hands on his hips, breathing a bit faster from the exertion.

"How long have you lived here?" I asked.

"Almost ten years." He was standing so close I could smell his toothpaste. It smelled minty, organic-I recognized it as Tom's of Maine, the old wintergreen flavor. "Turned out to be a great investment. I got it for $400,000. Last month the fixer-upper across the street sold for 1.7 million."

"You could cash out, move to the tropics, and take up a life of leisure." I thought of Peter McConnell in Nicaragua, living off the grid. I wondered what he was doing tonight, what he would make of my trek into Diamond Heights to confront the man who had ruined his life.

"Ah, yes," Thorpe said, "but what about my fans?"

"You can write anywhere."

"True, but then it's not really just about the writing, is it? You can write the best book ever, but if you're not around to do interviews, have your picture taken for magazines, show up at the book festivals, then your book is sunk, your readers evaporate, and you're alone with the blank pages."

"Is that why you do it-so you won't be alone?"

"Isn't that ultimately why anyone does anything?" He glanced out the window, then back at me. "Are you seeing anyone?"

"No one in particular."

I didn't like where the conversation was headed, but I wasn't sure how to get it moving in the right direction. I had come here to talk about Peter McConnell, and now I was distracted by the window. I imagined Thorpe sitting at his desk, watching the comings and goings of my childhood home. Until a year before, it would have been my mother he observed pulling out of the garage each weekday morning, my mother he saw traipsing down the street, yoga mat slung over her shoulder, on the way to her Sat.u.r.day afternoon cla.s.s.

And, of course, every Thursday night, he would have seen me, because every Thursday I came over for dinner. I would arrive at six, and my mother and I would have a gla.s.s of wine-either in the living room or on the back deck, depending on the weather. At six-thirty we would walk to Alice's at Twenty-ninth and Sanchez, where we would order pot stickers, orange chicken, garlic prawns, and bok choy. Around seven-thirty, we would climb the steep hill to my mother's house and stand on the sidewalk for a couple of minutes, saying our good-byes. This had been our routine ever since my father moved out after the divorce, and unless I was out of town or had something pressing to attend to, I honored the commitment. It was something we counted on, my mother and I. When she sold the house and moved to Santa Cruz, I had found myself on those Thursday nights feeling completely adrift. It had been such a regular part of my life for so long, I didn't know what to do with myself. Eventually I began filling the newly freed time with cla.s.ses-Bikram yoga, conversational Russian, Italian cooking, even hip-hop dance-but I always felt out of sync; the only place I wanted to be was in my old neighborhood, with my mother, talking casually about our week. During those Thursday-night dinners with her, I felt I could truly be myself, relaxed, with no need to put up my guard. Knowing that Thorpe had been there, probably watching us from above, cast the whole thing in a different light.

Although the clear view of my house was the most obvious topic, Thorpe simply pa.s.sed over it as if it did not exist. It was his way, again, of controlling the conversation, so that any dialogue advanced according to his own terms.

"There was a woman I was seeing for a while, a long time ago, before I met my ex-wife, Jane," Thorpe said. He was sitting on the edge of the desk now, legs crossed at the knees, hands resting at his sides, in a posture I remembered from cla.s.s. I sat down in the desk chair. "Her name was Florence, I called her Flo. We'd been together for a couple of months when I took her to a dinner party at the home of one of my former colleagues, Pio Schunker. Do you remember him?"

I thought for a moment. "Yes, he was the good-looking fellow with the unidentifiable accent and a taste for action movies. I had him for twentieth-century British lit. Whatever happened to him?"

"He ended up abandoning academia and becoming a major advertising executive, but that's beside the point. So we went to his house, and after dinner we were sitting in the living room having coffee when he said to Flo, 'Funny, the moment you walked in I thought you looked very familiar, and all night I've been trying to figure it out, and it just hit me.' At that point he turned to me and asked if I knew who he was talking about.

"Of course I knew," Thorpe continued, "but I'd never mentioned it to Flo, so I pretended to have no idea. 'You remind me of a student Andy and I used to have,' Pio said, 'Ellie Enderlin.'"

All this time, I'd been looking out the window. The light went off in the upstairs room of my childhood home. Thorpe stood and began pacing. Because the room was so small and overcrowded with furniture, he could only go three or four steps before turning around and pacing in the opposite direction. "What I'm trying to say is that I needed you."

The intimacy was too much, too fast. I felt myself instinctively leaning away from him, scooting the wheeled chair back a couple of inches.

He moved closer. "No, not in that way," he said, as if he were reading my mind. "Not that I would've objected-the night we spent together was terrific, I still think about it."

I backed away again. Again, he stepped closer. My chair was pressed against the bookshelves and I was looking up at him, his face tired and pale in the unflattering light of the new bulb.

"You were amazing, so open to me."

I remembered that night at his Dolores Park apartment differently. I remembered the bad lasagna he made, the strawberry cheesecake he served before it had completely thawed. I remembered sitting on the couch with him, well into our second bottle of wine, wondering how to extricate myself from the evening.

"But I'd have been fine with never touching you again if I could have had you in my life," Thorpe said. "Not as a romantic partner, as something more than that-a friend, an inspiration. Because I couldn't have you, I found someone who looked like you." He stopped pacing. "Funny, huh? Kind of pathetic. In fact, I have pictures. Come with me."

He was out of the room before I could protest. I followed him down the hall into a bedroom, and was surprised to see that the room was clean. The bed had recently been slept in, but only one side of the covers was turned down; the other half was in order, the pillows stacked neatly. The bedside table was clear except for a tidy stack of books, and the marks on the rug showed that it had been recently vacuumed. In the corner by the window stood a black leather Aeron chair, with a wool blanket folded over the back. The room was softly lit by a tall, modern lamp. This, too, was in keeping with the man I had known so many years before. Just when I thought I was beginning to understand him, I would be confronted with some aspect of his character that made me reevaluate.

"Don't look so surprised," he said. "I am at least capable of keeping one room of the house clean. I sleep better when I have no distractions."

He took a leather box off the chest of drawers, placed it on the bed, and removed the lid. The box was full of photographs. He began to go through them one by one. "I'm certain I have one in here," he said. "The two of you could be sisters."

As he searched, I caught glimpses of him as a young boy and as a teenager, mostly with his family-vacation snapshots from Disney World and Six Flags, Christmas morning pictures taken in front of a tree, a Polaroid of him and a young woman in a cap and gown at what appeared to be a high school graduation. He went too fast for me to get a good look at any of them, the effect being that I felt as though I was seeing a fast-forwarded version of his personal life. During all those hours I had spent spilling my heart to him, telling him the most intimate details of my life, he had revealed almost nothing about his own. There was a series of photographs of him in a gondola, and in each one-there must have been twenty or more-he was with a different girl.

"Where's this?" I said, taking one from his hand. The girl in this photograph was blonde, plump, and pretty, wearing a red gingham jumper and white Keds. She looked like the punch line to a farmer's daughter joke.

"Oh, the gondola ride in the harbor at Marina del Rey," he said. "For a couple of years during grad school at UCLA it was where I took girls on first dates. The girls seemed to like it, and I enjoyed the consistency. I figured if I put all of them on a level playing field-same date, down to the restaurant and the gondola ride-I'd have a better basis for comparison."

"Did it work?"

"I don't know that I ever went on a second date. None of them inspired me."

He flipped through a few more photos, and finally found what he was looking for. "Here," he said, thrusting a snapshot into my hand. "This is Flo."

The picture had been taken at Candlestick Park. Flo was sitting in the stands, holding a hot dog in one hand, a plastic cup of beer in the other. She was smiling, looking directly into the camera. Judging from the coat and scarf that she wore, it was a typical day at Candlestick, cold wind blowing off the bay. Lila and I had been to a few games there with our parents when we were kids, but I'd never been a big enough Giants fan to weather the frigid temperatures. When the Giants moved to the more comfortable China Basin in 2000, I began going to the games on a regular basis.

But this picture wasn't from China Basin, it was Candlestick. It could have even been a 49ers game. The woman in the photograph was pet.i.te, with strawberry blond hair and dimples, but the similarities ended there. I didn't think she looked much like me at all. Thorpe was living in his own little world.

He sat down on the bed and pulled me down beside him. "You were a turning point, Ellie. I was a frustrated writer, bored with my job, headed nowhere. Then you walked into my life, and everything changed. If I hadn't met you, Lila's story would have been no more to me than an item in the news, something I quickly forgot. Because of you, I stopped talking about writing a book and actually sat down and wrote one. You were my muse. Without you, I floundered."

"You wrote four more books."

"Yes, but they weren't the same. There's a reason everyone thinks my first book was my best. The others were forced-competent, maybe, because by then I knew what I was doing-but forced. Every sentence was an effort. With Murder by the Bay, the writing just flowed. During the day, I would see you, or at least talk to you by phone. At night, I wrote, energized by our conversations."

"You're leaving one thing out," I said.

"Hmm?"

"All that time, when I was talking to you about Lila, and about my family, you were using me. I considered you a friend, you considered me a source."

"It wasn't like that," he said, turning his whole body to face me. "People know Lila's name. Twenty years later, they're still talking about her. They love her. If it weren't for the book, she'd just be another dead girl."

"They don't love her," I said. "They're fascinated by her. To them, she's just a corpse somebody found in the woods, a catharsis. Anyone who reads that book feels relieved that it wasn't their daughter or girlfriend or sister. It's someone else's tragedy. Your readers can enjoy the spectacle, but they don't have to pay a price."

"You're wrong," he said, shaking his head. "That's not how it is at all."

I could tell that he believed what he was saying. He really believed he had turned Lila into some sort of cult heroine. In his version of the story, he'd done little wrong.

Twenty-one.

AT TWO IN THE MORNING THORPE AND I were sitting at the large gla.s.s-top table, facing each other over a half-eaten pizza and a near-empty bottle of wine. He'd insisted on feeding me, and the only thing he could find to cook was a frozen spinach and artichoke pizza from Trader Joe's. I was surprised how good it tasted, and how hungry I was. The wine was delicious, a 2003 pinot. I tasted raspberries and smoke, and poured myself a second gla.s.s. Thorpe was on his third.

I was all talked out, and yet I hadn't gotten any answers. Every time I tried to steer the conversation in the direction of Peter McConnell, he steered it back to something else. We talked about a recent trip he'd taken to Lisbon, an angry letter he'd received from the now ex-wife who was immortalized in Second Time's a Charm, and an early photograph by the Hungarian photographer Martin Munkacsi which he had recently acquired at considerable cost. I'd seen Munkacsi's spare, beautiful black-and-white photographs at the San Francisco Museum of Modern Art a couple of years before. The exhibit had featured famous portraits of American celebrities, aerial photos of female pilots, and the well-known "Three Boys at Lake Tanganyika." But the photograph Thorpe had purchased was from the early 1920s, when Munkacsi was at the very beginning of his career.

"Do you know Munkacsi's story?" Thorpe asked, lifting his gla.s.s.

"Didn't he take some iconic photo of Fred Astaire?"

"Yes, but what's really interesting is what came before all that, before he fled Hitler and moved to New York, back when he was completely unknown. One day Munkacsi was walking along with his camera when he came upon a street fight. He started taking pictures. By the end of the brawl, someone was dead. Munkacsi's photographs were used in court to clear the accused-this was what launched his career. I've managed to get my hands on one of these photographs of the brawl. It's being shipped from a gallery in Budapest next month. It will go right there, above the fireplace."

I imagined the image of a b.l.o.o.d.y street fight hanging above Thorpe's mantel, hovering over the room. What kind of man would want to gaze, every day, at a portrait of a murder-in-action?

"Lucky man," I said.

"I know. You should have seen me at the gallery, trying to talk the owner into parting with it. He was determined to only sell to a Hungarian. I was speaking through an interpreter, to whom I'd promised a handsome commission, and it turns out he did more than translate. He apparently made up some elaborate story about my ancestral connection to the Hapsburgs."

"I wasn't talking about you," I said.

"Pardon?"

"When I said 'lucky man,' I was referring to the man who was cleared of committing the crime."

"Oh," Thorpe said, "of course."

It was late, and I was afraid of leaving without getting what I'd come for. As a night owl, I was always aware of the coming daylight, could sense the minutes ticking away. All of my best conversations with Henry had occurred in the middle of the night. Sunrise had a way of putting an end to intimacy; the vulnerabilities men displayed in the middle of the night seemed to disappear with the moon and stars.

Thorpe picked up his knife and began cutting his pizza into small bites. I'd forgotten his annoying habit of treating his food like he was dissecting it.

"There's something I wanted to ask you about."

"How does anyone live without Trader Joe's?" Thorpe said. "I'd go hungry if it weren't for their frozen food aisle. Did I ever tell you I met Joe Coulombe once? At a fund-raising soiree for the LA Opera. He's a big opera fan."

"Peter McConnell," I said.

Thorpe peeled an artichoke off the pizza and ate it slowly, gazing intently at his plate. If I didn't know him so well, I would have thought he hadn't heard me. "Trader Joe's didn't get really huge until it was bought out in 1979 by one of the German brothers who own Aldi. People still think there's a California guy named Joe in a floral shirt and Panama hat running the whole show."

I was determined not to give up. "Did Peter McConnell do it?"

Thorpe blotted his lips with a napkin. "You read the book. You know my theory."

"I'm not asking about your theory. I'm asking whether he did it."

"Off the record?"

"Sure," I said. "Who am I going to tell, anyway?"

"He had opportunity. He had motive. Most of the circ.u.mstantial evidence certainly pointed in his direction."

"Most?"

"In any case like this, there are shades of doubt."

I poured the last of the wine into his gla.s.s. "When you wrote the book," I continued carefully, "were you doubtful?"

"Any rational person, given the facts, would experience an element of doubt. That's unavoidable."

"But in the book, you made it sound as though it had to be him."

Thorpe picked up his gla.s.s. "It did."

"Why?"

"Because if anyone else did it, it would have just been another sordid murder for the police ticker, suitable for nothing more than an item in the newspaper. But if McConnell did it, it was a great story-a young, beautiful math prodigy, murdered by her married lover, who knew that he would never be as brilliant a mathematician as she was." His voice had become slightly unsteady from the wine, and a shadow of stubble had reappeared on his head. "At the end of the day, everyone wants to be taken away by a great story. Everyone wants to read about people they're unlikely to meet in real life. From the moment I stumbled upon McConnell, I knew he was the character I'd been looking for, the one who had eluded me in all my previous attempts to write a novel."

"But your book wasn't a novel."

"Nonetheless, I had to think like a novelist. If I'd approached it as a straightforward piece of journalism, I never would have found the heart of the story."

"What if the character in your book is nothing like the actual man? What if McConnell didn't do it?"

"One can't rule out the possibility."

"You don't care that you might have ruined an innocent man's life?"

"It's a stretch to call him innocent," Thorpe said. "Let's suppose for a moment that he didn't kill Lila; he would still be guilty of having an extramarital affair, and of using your sister to further his ambition of proving the Goldbach Conjecture."

"When a book is labeled nonfiction, people expect to read the truth."

"Remember what Oscar Wilde said in the preface to The Picture of Dorian Gray: 'There is no such thing as a moral or an immoral book. Books are well-written or badly written.' Hopefully, mine was well-written and provided some pleasure. I was only trying to tell a good story. And the deeper I got into the book, the more clear it became to me that there could be only one ending. Once I understood what it was, writing the story was like following a map."

Thorpe leaned back. "Listen, I was thinking maybe we could get together soon. I'm doing a signing at Books Inc. in Opera Plaza on Sat.u.r.day. We could have lunch in the neighborhood afterward."