The Will to Believe, and Other Essays in Popular Philosophy by William James is a work of nonfiction originally published in 1896. Its title essay was originally a lecture given at the Philosophical Clubs of Yale and Brown Universities. In this work, James is attempting to explain complex philosophical concepts to a educated general audience. In other words, although it is not addressed narrowly to academic specialists in philosophy, it presumes a readership of people who are familiar with major western thinkers. Because it is a work of nonfiction, it does not contain imaginary characters but references a wide range of historical and contemporary figures. As its major concern is moral philosophy and religion, it engages thinkers who made major contributions to those fields. Some of the major thinkers with whom it engages are discussed below.

Biblical authors: Although the Bible evolved over a long period of time and had many different authors and editors, James is concerned about its overarching message rather than separating out the history of individual contributors to its composition. One of James's major contributions to religious philosophy was arguing that "belief" in the Bible was not dependent on the literal truth of its historical claims but rather the social and moral utility of religious belief. His thoughts about religion thus treated the major Abrahamic religions of Judaism, Islam, and Christianity, all of which he discussed, in terms of their social and psychological effects.

Louis Agassiz: William James worked with the acclaimed naturalist Agassiz, who influenced his thinking about close observation of the empirical world.

Charles Darwin: James was influenced by Darwin;s notion of instincts as driving the behavior of mammals and applied evolutionary theory to understanding human psychology and behavior.

Immanuel Kant: The seminal works of Kant influence James, especially in his understanding of the importance of the ways in which our impressions are mediated by concepts. He is also influenced by Kantian accounts of the mind, albeit with some admixture of Freud and other nineteenth century psychologists.

Charles Sanders Peirce: Although James was less concerned with semiotics and formal logic than Peirce, he owes a major debt to Peirce's concept pf pragmatism and the notion that one should look at ideas in terms of their application rather than as isolated abstractions.