Psychological transformations in psychotherapy spring from the encounter with paradox. The Zen koan, a seemingly nonsensical and self-contradictory statement, can serve as model for understanding the transformation process. Paradoxes exist within the personality dynamics of the individual as well as in the interpersonal relationship between therapist and patient, Zen master and student. Exploring paradox leads to the breakdown of rationality and intellect, a state of personal crisis, and the final act of "letting go" 'that precedes the freeing of the observing self and the insightful reframing of one's problems. Through the act of self negation, both the Zen student and psychotherapy patient tap a state of no-self that transcends paradox and is the source of spontaneity, empathy, and self-acceptance.