“Print dealers break these up,” he said, “but this is such a desirable volume and in such good condition I thought it really ought to go to an antiquarian book dealer.”

I nodded again, this time looking at moths. One was a cecropia. That and the luna are the only moths I know by name. I used to know others.

I closed the book, asked him what he wanted for it.

“A hundred dollars,” he said. “That’s less than two dollars a plate. A print dealer would charge five or ten a plate, and he’d get that easily from decorators.”

“Could be,” I said. I ran my finger over the book’s top edge, where a rectangle enclosed the stamped words New York Public Library. I opened the book again, looking for a Withdrawn stamp. Libraries do divest themselves of books, just as museums deaccession some of their holdings, though Duchardin’s Lepidopterae hardly seemed a candidate for such treatment.

“Those overdue charges can mount up,” I said sympathetically, “but they have these amnesty days now and then when you can return overdue books with no penalty. It seems unfair to those of us who pay our fines without protest, but I suppose it does get books back in circulation, and that’s the important thing, isn’t it?” I closed the book again, set it deliberately into his open attaché case. “I don’t buy library books,” I said.

“Somebody else will.”

“I don’t doubt it.”

“I know one dealer who has his own Withdrawn stamp.”

“I know a carpenter who drives screws with a hammer,” I said. “There are tricks to every trade.”

“This book didn’t even circulate. It sat in a locked case in the reference section, available by special request only, and because of its value they found ways to avoid letting people have access to it. The library’s supposed to serve the public, but they think they’re a museum; they keep their best books away from people.”