There are many things a reader forgets about a detective novel, but he always remembers the detective. Banker John Putnam Thatcher is less memorable than Hercule Poirot with his eccentricities, than Lord Peter Wimsey with his aristocratic savoir faire, or Adam Dalgliesh with his poeticizing and policing. Thatcher is an unlikely prospect for an amateur sleuth; in fact, he shades toward the bland and unassuming. He has no colorful hobbies, like Wimsey's collection of incunabula.

Like Dalgliesh, he has a family: a deceased wife, a daughter, and grandchildren. But they figure less prominently in the Lathen series than do Dalgliesh's domestic affairs in the P. D. James novels. Thatcher also has no distinctive accent or distinguishing facial hair like Poirot.

Thatcher is a clear-thinking, persistent, imaginative executive who uses both ratiocination and common sense to solve crimes. In Death Shall Overcome, he shows steadfastness and determination by holding...