“Rumfoord had known that Constant would try to debase the picture by using it in commerce. Constant's father had done a similar thing when he found he could not buy Leonardo's "Mona Lisa" at any price. The old man had punished Mona Lisa by having her used in an advertising campaign for suppositories. It was the free-enterprise way of handling beauty that threatened to get the upper hand.”

“Billy's smile as he came out of the shrubbery was at least as peculiar as Mona Lisa's, for he was simultaneously on foot in Germany in 1944 and riding his Cadillac in 1967.”

“If I had a euro for every stupid thing I've done, I could buy the Mona Lisa.”

“Rosewater was twice as smart as Billy, but he and Billy were dealing with similar crises in similar ways. They had both found life meaningless, partly because of what they had seen in war. Rosewater, for instance, had shot a fourteen-year-old fireman, mistaking for a German soldier. So it goes. And Billy had seen the greatest massacre in European history, which was the fire-bombing of Dresden. So it goes. So they were trying to re-invent themselves and their universe. Science fiction was a big help.”

“The Mona Lisa, the Mona Lisa....Leonardo had eye trouble....Art couldn't explain it....But now we're safe, since science can explain it. Maybe Milton wrote Paradise Lost because he was blind? And Beethoven wrote the Ninth Symphony because he was deaf...”

“Anna, Anna," Josh interrupts. "If I had a euro for every stupid thing I've done, I could buy the Mona Lisa. You'll be fine.”

“Echolalia is a mental disease which makes people immediately repeat things that well people around them say. But Billy didn't really have it. Rumfoord simply insisted, for his own comfort, that Billy had it. Rumfoord was thinking in a military manner: that an inconvenient person, one whose death he wished for very much, for practical reasons, was suffering from a repulsive disease.”