William James was an esteemed scientist credited with bringing laboratory science to the study of psychology. Trained as a medical doctor and a physiologist, James insisted that mental processes--thought and consciousness--originated from physical processes, that is, the actions of nerves, muscles and glands. His monummental Principles of Psychology assimilated much earlier research, and grounded psychology as a natural science. In spite of his pivotal role in the development of American psychology, James left the field behind later in his life, and concentrated on philosophy.

William James was born January 11, 1842, eldest son of a theologian. It was a distinguished intellectual family. James's younger brother was the novelist Henry James. The James children were educated somewhat haphazardly, as the family traveled between New York, Boulogne, France, and Geneva. William James was multi-lingual at an early age, and in his father's company he was exposed to many religious and philosophical thinkers...