Philip Elliot Slater (May 15, 1927 – June 20, 2013) was an American sociologist and writer. He was the author of the bestselling 1970 book on American culture, The Pursuit of Loneliness and of numerous other books and articles.
He had an A.B. and Ph.D. from Harvard and taught sociology at Harvard, Brandeis, and University of California at Santa Cruz. He was Professor and Chairperson of the Brandeis Sociology Department in 1971 when he resigned to found, with Jacqueline Doyle and Morrie Schwartz, Greenhouse, a non-profit growth center, where he led encounter groups and personal growth workshops.
He was a merchant seaman, actor, business consultant, cookie salesman, marriage officiant, and president of a theatre. He collaborated with filmmaker Gene Searchinger on Paradox on 72nd Street, a one-hour TV documentary aired nationally by PBS and acted in over 30 plays and films. In 1982, he was chosen by MS. Magazine as one of its "male heroes". Slater taught writing and playwriting at UCSC and in private workshops starting 1989. He returned to academia in his eighties, teaching in the doctoral program in Transformative Studies at the California Institute for Integral Studies .
Besides the influential 1970 bestseller The Pursuit of Loneliness , Slater was the author of nine other books of sociology and social commentary. He wrote more than 25 novels and plays. In a prescient 1964 Harvard Business Review article called, "Democracy is Inevitable," he and co-author Warren Bennis predicted the fall of the Soviet bloc and the rise of democracy: “Democracy... is the only system that can successfully cope with the changing demands of contemporary civilization.” Slater believed fervently in democracy's adaptive superiority, an idea he would later develop in his last two books of nonfiction, A Dream Deferred (Beacon 1992)  and The Chrysalis Effect (Sussex Academic Press 2008) .
He died of cancer in Santa Cruz, California at 86.
- San Francisco Chronicle Author, Harvard LSD tester Philip Slater dies
- Slater, Philip (1990). The Pursuit of Loneliness. Beacon Press. ISBN 0-8070-4201-3.
- Vitello, Paul (29 June 2013). "Philip E. Slater, Social Critic Who Renounced Academia, Dies at 86". The New York Times. Retrieved 6 July 2013.
- O'Connor, John J. (January 5, 1982). "TV: 'AMBUSH MURDERS,' BASED ON TRIAL". The New York Times. Retrieved 25 December 2016.