Pragmatism — William James's 1906–1907 Lowell Institute and Columbia University lectures: pragmatism as a philosophical method that clears metaphysical disputes by asking what concrete difference each alternative makes in practice.
The Varieties of Religious Experience — Mysticism — William James's Gifford Lectures XVI and XVII (1902): the phenomenology of mystical consciousness, from its four marks through yoga, Sufism, Christian mysticism, and James's three-part assessment of its authority.
The Will to Believe — William James's 1896 defence of the right to adopt a believing attitude in religious matters even when logical intellect has not been coerced — the case for voluntary faith as a live, forced, and momentous option.