“If he did,” the professor said drily, “it gets filed under No Good Deed Goes Unpunished. Listen: ‘Later that evening Chen’s sister, Mei-lin, arrived at Number 76.’ ”

“Paul!” I turned to Bill. “That’s who told us about Number 76.”

“Who’s Paul?” Dr. Edwards demanded.

“Paul Gilder. Rosalie’s brother.”

“The brother’s still alive?”

“He’s got Alzheimer’s, or something like it. He thinks I’m Mei-lin. We can’t really question him, but he started talking about those days, rambling. We didn’t understand most of what he said, but he mentioned Mei-lin going to Number 76 and being brave. I wonder how much of this is in Mei-lin’s diary?”

“Her diary?”

“It’s in Chinese. I’ve just started translating it. He-Paul-had it all these years. No one’s read it. But it stops-”

“No one’s read it? An undiscovered primary source? Calloo callay! Can I see it?”

“I-I suppose so.”

“She supposes so! Oh heavenly joy! What else you got?”

“Nothing.” I wasn’t ready to admit to Rosalie’s unread letters; I was queasy about us reading them ourselves. “Except some old men who were there.”

“Military men?”

“No. The sons.”

“Whose sons?”

“Everyone’s. Kai-rong’s, Mei-lin’s-”

“The son and nephew Kai-rong sent here?”

“Yes. And General Zhang’s older son.”

“By his first wife?”

“You know about him?”

“I know about everybody. These men are still around? You’ll introduce me?”

“Well, okay, yes. Though I don’t know-”

“Whether they’ll talk to me? That’s my problem. Cracked some tough nuts in my time, I have. Okay, on that basis, and even though Larry sent you, I’ll go on.” He picked the book up again. “Now pay attention. Because we’re getting to the ‘brave’ part, I bet. ‘The sister stated to the captain in charge at Number 76 that her brother was not a Communist spy, but her husband was.’ ”

“My God,” I said. “Was that true?”

“Have patience. Quoting again: ‘She offered to turn over husband’s list of CCP agents if her brother was released. Police officials considered locking her up, taking list by force. Decided against that, fearing her father had influence with Japanese. Chen Kai-rong freed. Sister handed over list, handwritten, not in Chen Kai-rong’s hand. Three men on it previously suspected by SMP, so authenticity seemed probable. SMP went forward with plan to round up agents, then General Zhang. When agents’ homes and businesses raided that night, however, all had fled. Chen Kai-rong, Mei-lin, General Zhang also gone. Chen’s Austrian wife briefly arrested, released soon after. Appeared to have no inkling husband was CCP. Credible: Jewish refugee, no knowledge of Chinese politics, likely married him for his money.

“ ‘Chen reportedly made his way north to Red Army. General Zhang turned up in Chongqing with older son. Reported to have put his personal fortune at Chiang’s disposal as token of earnest repentance at having served puppet government and evidence of sincere resurgence of patriotism.’ ” The professor looked up. “Some of these navy guys had dry senses of humor.” Back to the book: “ ‘Zhang in Nationalist military, commanding army brigade, since. No further word on Mei-lin.

“ ‘Assessment of potential usefulness of Chen Kai-rong to U.S. interests: low. Later intelligence suggests Mei-lin’s statement false. Probably had two intended results: to free brother and discredit husband. Domestic relations reported not good. List likely to have been Chen’s, as suspected, copied over in her hand. Further reports indicate agents on list tipped off, probably her doing. Interrogation of Zhang servants indicated general, Mei-lin, and older son fled hours ahead of SMP raid. Driver said Mei-lin tried to break away, forced onto train. Not with general and son in Chongqing. Zhang presumed to have killed her.’ ”

I couldn’t help it: “Oh, no!”

Dr. Edwards peered over the book. “She screwed him. Ruined him. He was a high-ranking collaborationist and she fingered him for a Commie spy. It cost him his whole fortune to buy his way into Chiang’s army, where he actually had to fight battles and stuff. You bet he killed her.”

He went back to the book while I thought about Mei-lin. Be careful what you wish for.

“ ‘Chen reported to have returned secretly months later, in and out of Shanghai since. To this date, has managed to elude Nationalist capture. Presumed to be continuing CCP intelligence work.

“ ‘Recommended action: none. Continue surveillance. No contact unless situation changes.’ ”

Dr. Edwards plopped the report down. “The end. So. Does that tell you what you want to know?”

“Yes. And no,” I said. “Chen Kai-rong really was a Communist all along?”

“Looks that way. But remember, in those days they were the good guys. The peasants were starving, and Mao’s people were their only hope. And you want towering heroism, you can’t do better than some of these early Communists. That’s how revolutions are. Before politicians get hold of them.” Dr. Edwards looked wistful.

“While we’re bemoaning the perversion of the insurrectionist spirit,” Bill said, “tell us this: Are there details in there about his wedding?”

“His wedding? His wedding? I’m giving you blood and thunder and you want shoes and rice?”

“I’ll take that as a no.”

“Don’t. You’re looking for sweet domesticity, I got your sweet domesticity right here. U.S. National Archives. Unbelievable what’s maintained at taxpayers’ expense. Who reads German?”

“I do,” said Bill, while I shook my head.

Dr. Edwards, looking not at all surprised, handed Bill a sheet of paper. “From Die Gelbe Post. One of the ghetto newspapers. Anyone want a Coke?”

He strode off to the vending machines. I craned my neck to see what Bill held: a photocopy of a blurred newspaper page. Rosalie Gilder’s name headlined one column. I hoped for a photo, but no. “What does it say?”

“It’s from May 1942. Just an announcement. Rosalie Gilder married Chen Kai-rong-it calls him ‘a Chinese gentleman’-in a civil ceremony before a judge. As Chinese law requires for foreigners’ weddings, the ceremony was held in a public place, in this case the Café Falbaum on Tongshan Road. At a reception afterward, guests were served wine, schnapps, tea, espresso, red bean cakes, and linzer torte.”

“Does it-”

“Yes it does. The bride wore a simple white dress and the groom a silk scholar’s robe. The bride, at her throat, wore a brooch of jade and diamonds.”

“That’s all?”

“That’s all.”

“What’s all?” Dr. Edwards dumped an armful of Coke cans and bags of peanuts on the desk. He handed out mugs, poured his Coke, and dropped in a handful of peanuts. The Coke fizzed and foamed. I stared.

“Only way to do it, where I come from.”

“Me, too.” Bill did the same.

“I never in my life saw this before,” I said. “It’s disgusting.”

“I thought I heard Dixie in your voice,” Dr. Edwards told Bill. “Where y’all from?”

“Louisville.”

“Bah! You ask me, that’s the west. Macon.”

They raised their foaming concoctions and toasted each other.

“Now that we’re kissin’ cousins,” Dr. Edwards said, “suppose you elaborate a little more, why you care about this fellow?”

Bill and I took turns explaining and sipping Coke. I ate my peanuts the normal way.

“Well, by gosh and by golly.” Dr. Edwards pitched his empty can into the trash. “The Shanghai Moon! You can’t be in my business and not have heard of that. Pretty much everybody thinks it’s a myth. Or that maybe it was real once, but it’s gone gone gone. However, it’s my experience that, with the exception of Larry the molecular biologist, pretty much everybody’s wrong.”

“You do have your uses,” I told Bill as we emerged from the lamplit Columbia campus into the real world.

“I do. Another would be to drive you home. Unless you want to stop for coffee or something?”

“No, I’m exhausted. I just want to get somewhere quiet and absorb all this. You think it’s true?”