There is no handy rule of thumb, no blanket explanation for why a crime goes unsolved. Sometimes the sheer multiplicity of possibilities defeats investigators, as in a carefully executed murder from which many people stand to gain something, if only revenge. There are crimes so mystifying, so unusual, so devoid of clues or comprehensible motive, that the cleverest detectives are stumped. On these misdeeds the books remain open, growing dustier with the years. But the mysteries themselves never dull with time. They still keep people guessing. This book contains several cases in which the murderer could have gotten lost in such a crowd.