William James (1842-1910) was one of the founders of modern Psychology. He exercised a positive and pragmatic influence on the development of the young science. William James was the brother of novelist Henry James, with whom he shared a powerful command of the English language. William James' Principles of Psychology (1890) took him over a decade to write and amounted to 1500 pages. James was a considerable reader and had absorbed much of the writings of the Scottish, English, French and German schools of Psychology but he produced his own interpretations of the subject. In his 'Principles', James defined Psychology as the 'science of mental life'.
William James and the
Principles of Psychology