Over the past thirty-five years, there has been an explosive increase in scientists' ability to explain the structure and functioning of the human brain. While psychology has advanced our understanding of human behavior, various other sciences, such as anatomy, physiology, and biology, have determined the critical importance of synapses and, through the use of advanced technology, made it possible actually to see brain cells at work within the skull's walls. Here Jean-Pierre Changeux elucidates our current knowledge of the human brain, taking an interdisciplinary approach and explaining in layman's terms the complex theories and scientific breakthroughs that have significantly improved our understanding in the twentieth century.