Richard A. Warshak (born December 18, 1949) is an American clinical and research psychologist and author. He is best known for his research and advocacy in the areas of child custody, shared parenting, and claims of parental alienation in the context of divorce. Warshak has written two books, The Custody Revolution, and Divorce Poison: Protecting the Parent-Child Bond From a Vindictive Ex, and the updated edition, Divorce Poison: How to Protect Your Family from Bad-mouthing and Brainwashing.