Years ago, bookseller and mystery aficionado Malcolm Kershaw compiled a list of the genre's most unsolvable murders, those that are almost impossible to crack--which he titled "Eight Perfect Murders"--chosen from among the best of the best including Agatha Christie's A. B. C. Murders, Patricia Highsmith's Strangers on a Train, Ira Levin's Death Trap, A. A. Milne's Red House Mystery, Anthony Berkeley Cox's Malice Aforethought, James M. Cain's Double...