"Herbert Marcuse (1898-1979) was a little-known German scholar when he became one of the 20th century's most unlikely pop stars: a celebrity philosopher. In the 1960s, his argument for a "principled utopianism" catalyzed the ideals of a rebellious generation, and Marcuse became an intellectual guide for activists and revolutionaries around the world. The legacy of his contribution to a radical shift of consciousness has resonated in social-change movements ever since."