*The Book of Lies* (1913) is an esoteric prose-poetry collection by Aleister Crowley, the founder of Thelema, consisting of 93 short chapters whose subjects are determined by Qabalistic numerology. Each chapter is a dense, often enigmatic statement — ranging from a single word to several paragraphs — drawing on Hermeticism, Freemasonry, sexual mysticism, and Crowley's own system of magick, with accompanying authorial commentary explaining the symbolism. The work's central conceit, embedded in its full title, is that all language and thought are inherently false, meaning the "lies" of the text are paradoxically its most truthful utterances. Crowley claimed the book inadvertently contained the supreme secret of the O.T.O. (Ordo Templi Orientis) in plain language before he himself recognized it, a secret the Order's head later identified — an anecdote that underscores the text's layered, cryptic character. The work demands familiarity with Qabalah, Tarot, Greek letters, and Thelemic theology to decode, and Crowley himself described it as his most comprehensive philosophical statement despite its apparent obscurity and deliberate misdirection. Readers interested in early 20th-century occultism, Western esotericism, or the intersection of mysticism and avant-garde literary form will find it a primary source, but it rewards only those prepared to invest in its elaborate symbolic system.