I'm OK You're OK: A Practical Guide to Transactional Analysis (1969) by Thomas A. Harris, M.D. This book is the culmination of the experience of a 25 year medical career. "Transactional Analysis is a new breakthrough, one that confronts the individual with the fact that he is responsible for what happens in the future, no matter what has happened in the past. It is both a teaching and a learning device. It distinguishes three active elements in each person's make-up: the Parent, the Adult, and the Child (P-A-C)." 278 with index.