Immanuel Wallerstein was an American sociologist and historian best known for developing the World-Systems Theory. This theory analyzes the global economic system, emphasizing the relationships between core, semi-peripheral, and peripheral nations. Wallerstein argued that the world is interconnected and that economic and political power is distributed unevenly across different regions. Born on September 28, 1930, Wallerstein's work has influenced various fields, including sociology, political science, and history. He published numerous books and articles, with his most notable work being "The Modern World-System," which outlines his ideas about capitalism and its impact on global dynamics. Wallerstein passed away on August 31, 2019.