Book excerpt: A great recurring character in a series you love becomes an old friend. You learn about their strange quirks and their haunted pasts and root for them every time they face danger. But where do some of the most fascinating sleuths in the mystery and thriller world really come from? What was the real-life location that inspired Michael Connelly to make Harry Bosch a Vietnam vet tunnel rat? Why is Jack Reacher a drifter? How did a brief encounter in Botswana inspire Alexander McCall Smith to create Precious Ramotswe? In The Lineup, some of the top mystery writers in the world tell about the genesis of their most beloved characters -- or, in some cases, let their creations do the talking.