"it was William James's Principles of Psychology"

Classic text in the subject of psychology by William James, published in 1890. The entire text is available online.

James's method consists of analysis, introspection, experiment, and comparison. The text concerns itself with mind–body dualism, perception (of time, of space, and of reality), and the processes of logic and emotion.

Also included is a chapter on hypnotism, and some of its benefits.