This chapter reviews James’s approach to knowledge – its empirical and conceptual rationale, its nature, and its limits – and shows its relation to his psychology. Using James’s own metaphors of blazing trails and sculpting statues, it presents a humanistic approach to knowledge as a very human creation dependent upon the translation of the “much-at-once” flow of sensory experience into conceptual schemes reflecting human interests and ingenuity. Citing James’s arguments in works produced after The Principles of Psychology, it emphasizes the steady development of human knowledge in relation to practical feedback regarding the relative usefulness or non-usefulness of alternative forms of conceptual understanding. The inheritance of age-old conceptual categories and the appearance of new ones reflect the social nature of knowledge and the importance of the social exchange of conceptual schemes. The argument is made that James’s pragmatic view of knowledge-formation and knowledge-development is particularly apt in the post-Einsteinian world in which longstanding “truths” have been rejected and modified. The thrust of James’s approach is toward ever-increasing and ever-improving knowledge rather than belief in the immanent attainment of final truths.