The development of series characters in fiction is almost always a triumph of commerce over art. No matter how interesting a character is, there is usually one right story about him or her, and a good writer finds it the first time. Shakespeare got just one play each out of Hamlet and Macbeth, and it is hard to imagine what remained for a sequel -- or prequel.
Readers, however, have an all but boundless appetite for revisiting accustomed pleasures. That is nowhere more true than in the mystery, whose audiences manifest, by their choice of genre, a taste for restoring established...