Marat, a central character in one of history's most significant social transformations, has been alternately hailed as a heroic leader in the French Revolution and condemned as a bloodthirsty fanatic. During the Revolution, Marat was a crusading, agitational journalist. Before the Revolution, however, he was a scholar, scientist, and medical doctor. Unlike previous biographies, which have concentrated on the last four years of his fifty-year life, this one covers both of Marat's "two lives."