William James was one of America`s most original thinkers and worked in several fields -- psychology, physiology, and theology. Born in New York City in 1842, he attended Harvard and took part in an expedition on the Amazon River with Louis Agassiz in 1865. After receiving his medical degree from Harvard in 1871, he began teaching undergraduates at Harvard in 1874.
His most important work was Principles of Psychology, published in 1890. The late years of his life produced a fresh burst of literary output. He died in 1910.