Kenneth Waltz
Kenneth Waltz is one of the most influential scholars in modern international relations theory (ref) and a major founder of the school of thought called neorealism (or structural realism), which argues that the structure of the international system guides state behavior. He is best-known for his books Man, the State, and War and Theory of International Politics, both of which are classics in the field. In recent years he has also made waves for his somewhat controversial views on nuclear proliferation.