In this stimulating volume, Sir Isaiah Berlin lucidy and succinctly presents commentaties on, and selections from, the basic writings of the brilliant philosophers Berkeley, Locke, Hume, and others - women who believed that science's achievements in the material world could be translated into philosphical terms. The challenging ideas of these great thinkers - and their equally great critics - remain the classical foundation of liberal humanism and rationsim in the West, so unparalleled for their lucidity, courage, hatred of darkness, and love of truth that they are of vital interest to men and women today.