Kenneth N. Waltz (1924-2013) is a significant figure in international relations, particularly for developing the theory of neorealism, which emphasizes the anarchical nature of the international system and the behavior of states. His key works include 'Man, the State and War' (1959) and 'Theory of International Politics' (1979), where he asserts that states are rational actors that seek to maximize power in an inherently competitive environment. Waltz's framework highlights the importance of the distribution of capabilities among states and the concept of balance of power, arguing that these factors shape state interactions and the potential for conflict.