Casino Royale by Ian Fleming (Thomas & Mercer, $15). Fleming was disillusioned after World War II and had a girlfriend who was pregnant, which back then meant a reluctant marriage. So he briefly escaped to Jamaica and wrote a spy novel he didn't think was very good. But a publisher took a chance, and James Bond became an icon. What if there'd been no pregnancy?

The Deep Blue Good-by by John D. MacDonald (Random House, $16). MacDonald, also restless after the war, broke away from his prosperous background to become a prodigious pulp wordsmith — Westerns, sci-fi, anything to pay the rent. Until, in the early '60s, he dreamed up a leathery boat bum named McGee and launched one of the greatest series ever. What if MacDonald had gone to work for GM?

Postmortem by Patricia Cornwell (Pocket Star, $10). Authors can become soap-opera stories, but never if there wasn't good reason for their coming to prominence in the first place. Postmortem was a very good reason: It single-handedly invented the "CSI" forensics genre. What if Cornwell had stayed working in a crime lab?

The Black Echo by Michael Connelly (Grand Central, $6). When Connelly was a kid, he saw a guy hide something in a hedge, sneaked a look, and found a used handgun wrapped in a dirty shirt. So was born a unique talent for making everyday police procedure utterly gripping. What if it had just been a shirt in the hedge?

Los Alamos by Joseph Kanon (Island, $8). Joseph Kanon was a successful publishing exec who grew tired of commuting from New York to Boston. So he quit and tried his hand at writing, mining recent history for fascinating stories, starting with the A-bomb's development. What if his job had been just a subway stop away?

Maisie Dobbs by Jacqueline Winspear (Penguin, $15). Winspear was struggling to find time to write when she badly broke her arm in a fall from a horse. A whole story flashed inside her head — about a servant who became a World War I nurse and then a kind of psychological profiler. But what if there'd been no fall from a horse?

Lee Child is the best-selling author of 17 Jack Reacher novels. Jack Reacher, the movie based on the book One Shot, will be released on DVD May 7.