Thomas Anthony Harris (April 18, 1910 – May 4, 1995) was an American psychiatrist and author who became famous for his self-help manual *I'm OK, You're OK* (1967), which was a bestseller. Harris was a long-time friend and associate of Eric Berne, the founder of Transactional Analysis, beginning when both men were among the few psychiatrists in the U.S. military. He was also a founding member of Berne's San Francisco Transactional Analysis Seminar, which met weekly for over a decade, and which developed the main concepts of TA. A Teaching Member of the International Transactional Analysis Association, Harris was an early advocate for group therapy and TA in preference to traditional psychoanalysis, for which he was trained by Harry Stack Sullivan. Source: [Wikipedia](https://en.wikipedia.org/wiki/Thomas_Anthony_Harris)