Bittersweet Destiny combines a discourse on the evolution of human behavior with a philosophical perspective. It explores evolutionary theory aimed at determining human behavior. Thiessen presents material against the broad background of everyday life, allowing the reader to see the theory of evolution as it has shaped his or her own behavior. However, he points out that when evolution theory is aimed at human behavior, the critics object, and controversy results.

Bittersweet Destiny describes the heroic efforts of naturalists Charles Darwin and Alfred Wallace to unlock the secrets of evolution. It continues with a vivid description of our fossil history and our chance beginning. From there the story implicates disease processes in evolution, highlights our irrational and rational nature, focuses on those characteristics of brain evolution and language that make us distinctive, and illustrates our most basic survival and reproductive mechanisms.

Thiessen warns the reader that things are as they are no matter what we might wish; we ignore facts and controversy at our own risk. To this end Bittersweet Destiny draws out the evolutionary argument to its logical end - no holds barred. It will be of significant interest to anthropologists, psychologists, biologists, and sociologists.