A child is one hundred times more likely to be abused or killed by a stepparent than by a genetic parent, say two scientists in this startling book. Martin Daly and Margo Wilson show that the mistreatment of stepchildren, long a staple of folk tales, has a solid basis in fact; Daly and Wilson apply the perspective of evolutionary psychology to investigate why stepparenthood is different from genetic parenthood and why steprelationships succeed or fail.