Democracy, free thought and expression, religious tolerance, individual liberty, political self-determination of people, sexual and racial equality - these values have firmly entered the mainstream in the decades since they were enshrined in the 1948 U.N. Declaration of Human Rights. But if these ideals no longer seem radical today, their origin was very radical indeed - far more so than most historians have been willing to recognize. In "A Revolution of the Mind", Jonathan Israel, one of the world´s leading historians of the Enlightenment, traces the philosophical roots of these ideas to what were the least respectable strata of Enlightenment thought - what he calls the Radical Enlightenment. Originating as a clandestine movement of ideas that was almost entirely hidden from public view during its earliest phase, the Radical Enlightenment matured in opposition to the moderate mainstream Enlightenment dominant in Europe and America in the eighteenth century.