A founder of the field of evolutionary medicine uses his decades of experience as a psychiatrist to provide a much-needed new framework for making sense of mental illness.

Why do I feel bad? There is real power in understanding our bad feelings. With his classic Why We Get Sick, Dr. Randolph Nesse helped to establish the field of evolutionary medicine. Now he returns with a book that transforms our understanding of mental disorders by exploring a fundamentally new question. Instead of asking why certain people suffer from mental illness, Nesse asks why natural selection has left us all with fragile minds.