The Principles of Psychology

A two-volume textbook, twelve years in the writing, that helped found psychology as a science in the United States while remaining a work of philosophy. James surveys brain function and the experimental work of his day, but the book is best known for its descriptive chapters. "Habit" presents habit as the flywheel of society and gives practical advice on forming good habits. "The Stream of Thought" describes consciousness as a continuous, ever-changing flow rather than a chain of separate ideas, with a "fringe" of vague relations around each thought. "The Consciousness of Self" divides the self into material, social and spiritual parts and argues that a person has many social selves. Other chapters treat attention, memory, the perception of time, including the "specious present", and the will. The chapter on emotion sets out the James–Lange theory that emotion is our feeling of bodily changes.

It contains some of the clearest writing ever done on habit, attention, the self and the stream of consciousness, and many of its ideas still frame debates in psychology and philosophy of mind.