The detective story--the classic whodunit with its time-displacement structure of crime--according to most literary historians, is of relatively recent origin. Early in its development, the whodunit was harshly criticized for its tightly formula-bound structure. Many critics prematurely proclaimed "the death of the whodunit" and even of detective fiction altogether. Yet today, the genre is alive, as contemporary authors have brought it into modern times through a significant integration of elaborate character development and psychology. With the modern psychological detective story emerging from the historical cauldron of detective fiction and early psychology, the genre continues to develop a complexity that reflects and guides the literary sophistication needed. This book, the first of its kind, analyzes over 150 whodunit novels and short stories across the decades, from The Moonstone to the contemporary novels that saved the genre from an ignominious death.