What are the origins of the concepts under which we organize societies, create institutions, and think about our lives? Where did the concept of God or equal rights or democracy come from? How does one idea influence another? Such questions fuel debates, speeches, position papers, and assignments in history classes, ethics classes, etc. The original 1974 "Dictionary of the History of Ideas" has long been admired as a landmark document encapsulating the thinking of an era. This thoroughly re-envisioned "New Dictionary of the History of Ideas" brings fresh intelligence and a global perspective to bear on timeless questions about the individual and society.