About the Book: In The Four Realms of Existence, renowned neuroscientist Joseph LeDoux redefines what it means to be human through a groundbreaking theory of consciousness and evolution. Dividing our origins into four interconnected realms—bodily, neural, cognitive, and conscious—LeDoux reveals how life evolved from simple organisms to self-aware beings. Blending neuroscience, psychology, and philosophy, this compelling work challenges the idea of a single “self” and presents a unified vision of human existence.