A psychoanalyst and Zen practitioner explores how koan practice can function as a therapeutic technology, showing how these paradoxical teachings expose defenses, habitual patterns, and relational dynamics to catalyze deeper integration. Combining historical overview, close readings of koans, and clinical vignettes, the book argues that koans do not offer an escape from suffering but a disciplined, ethical encounter with the unconscious that transforms how one lives and relates to others. It challenges romanticized notions of sudden enlightenment and emphasizes sustained practice, self-reflection, and the interplay between psychotherapy and Zen insight.