After fifty years, Paul Baran and Paul Sweezy's Monopoly Capital has stood the test of time. Not only did it provide a lucid description of midcentury American society, but Monopoly Capital established a framework for analyzing events to come.… By bringing Marxian theory into their historical moment, they fomented many debates and encouraged the development of various perspectives, a legacy that has expanded to include analyses of the labor process, imperialism, finance, globalization, and the environment.… They elucidated a fundamental contradiction of the time. Capitalism is a system of self-expanding value that must continually accumulate, yet is confined by a social and institutional order that precludes rapid accumulation. This framework is especially useful for analyzing the fundamental problems of the twenty-first century. Among those crucial problems is the demise of the hydrocarbon economy.