Harry Allen Overstreet (October 25, 1875 – August 17, 1970) was an American writer and lecturer, and a popular author on modern psychology and sociology. His 1949 book, The Mature Mind, was a substantial best-seller that sold over 500,000 copies by 1952.

Overstreet was born in San Francisco, California, on 25 October 1875. He attended the University of California receiving his B.A. degree in 1899. He taught at Berkeley until 1911. From 1911 to 1936, he was chair of Department of Philosophy and Psychology at City College of New York. Overstreet also taught in the continuing education program of the New School for Social Research. He lectured and worked frequently with his second wife, Bonaro Overstreet. (Sourced from Wikipedia May 2023)