Noam Chomsky's linguistic theories revolutionized the field, and he is also known as a political radical. He has written many works of social, political, and economic analysis, and his latest work "Towards a New Cold War," consists of essays tracing the evolution of American foreign policy and ideology since the 1970s. A new collection of his essays called "Radical Priorities," has also been released. Chomsky, who grew up in the area, is in Philadelphia to deliver a talk on the relations between the United States and Israel.