A framework book that explains how rational thinking differs from IQ, and why rationality is more important. The book argues that IQ measures only part of human cognitive ability and doesn't measure the rational thinking skills that actually drive good decisions. The author introduces the concept of dysrationalia (smart people making stupid decisions) and builds a detailed taxonomy of reasoning errors that explains what causes those bad decisions and how to correct them. The most interesting of these are mindware gaps and contaminated mindware.