I underestimated the mystery reader, and I apologize. I realize now that it takes much more commitment—character, even—to read Miss MacInnes than it does to go through Thomas Mann or Marcel Proust. There is so much to remember that isn't memorable.

Secret drops, code names, cover techniques, labyrinthine motives, alternative procedures, espionage bureaucrats: one needs energy, patience, doggedness, a photographic memory. One needs a reason, too, not the get-away-from-it-all impulse I naïvely supposed, but the determination of a man working for a Ph.D.

Why do they do it?… Perhaps a Helen MacInnes novel is the mental equivalent of jogging.

I was struck by the familiar warning after the title page: "The characters in this novel are completely imaginary. Their names and experiences have no relation to those of actual people."… It's absolutely true in this case. I have never met any actual people who...