William James (1842-1910) is a canonical figure of American pragmatism. Trained as a medical doctor, James was more engaged by psychology and philosophy and wrote a foundational text, Pragmatism, for this characteristically American way of thinking. Distilling the main currents of James's thought, William J. Gavin focuses on "latent" and "manifest" ideas in James to disclose the notion of "will to believe," which courses through his work. For students who may be approaching James for the first time and for specialists who may not know James as deeply as they wish, Gavin provides a clear path to understanding James's philosophy even as he embraces James's complications and hesitations.