The readings collected here--of Karl Marx, Friedrich Engels, Rosa Luxemburg, Vladimir Ilyich Lenin, Leon Trotsky, and Antonio Gramsci-- reflect the experience of the labor, socialist, and communist movements that did so much to shape modern history. A dedication to working-class revolution gives coherence to the influential philosophical, economic, sociological, and historical works of these writers. Paul Le Blanc's introductory essay probes the structure and dynamics of Marxism as a political orientation, tracing connections among components that can be found in the readings: the theory of capitalist development, the theory of the labor movement, the strategy of revolution, the conception of the transition to socialism. Others identified with the Marxist tradition--such as Plekhanov, Kautsky, Stalin, Mao--are also discussed, and attention is given to perspectives of such varied critics of Marxism as Sidney Hook, Bertram D. Wolfe, James Burnham, Daniel Bell, Robert Heilbroner, and C. Wright Mills. Historical reflections are blended with discussion of the durability of capitalism, the disappointment of hopes for workers' revolution, the "collapse of communism," issues of race and gender, the environment, and challenges of the twenty-first century.