The Critical Psychology founded by Klaus Holzkamp began with a critique of the function of psychology as a science of domination and a methodology that only captures behavior as an arrangement under externally imposed conditions. The introduction outlines how this critique evolved into a Marxist subject science. As such, it aims to bring to light possibilities that are still theoretically misunderstood in traditional psychology and practically hindered in capitalist society. It presents how to gain this emancipatory perspective using the categories of Critical Psychology and its theoretical, methodological, and practice-related concepts, as well as the concrete problems that arise in this process. Reflections on the tasks for further development of Critical Psychology conclude the volume.