Abbot Howard "Abbie" Hoffman (November 30, 1936 – April 12, 1989) was an American political and social activist who co-founded the Youth International Party ("Yippies") and was a member of the Chicago Seven. He was also a leading proponent of the Flower Power movement. Hoffman continued his activism into the 1970s, and remains an icon of the anti-Vietnam war movement and the counterculture era. He died of an intentional phenobarbital overdose in 1989 at age 52.