One of the founders of Radical America in Madison, Wisconsin, while a student at the University of Wisconsin, O'Brien continued to contribute to or edit the journal following its move to Somerville, Massachusetts (circa 1970). A pamphlet version of O'Brien's New Left research was published in 1969 as “A History of the New Left, 1960-1968,” following its appearance in three installments in Radical America in 1968.
