What is alienation? Does the increase in burnouts and depression indicate that the critical assumption that humans have become alienated from themselves in modernity is more accurate today than ever? Or is this diagnosis, made by authors such as Rousseau, Hegel, and Marx, hopelessly outdated because it is based on problematic assumptions like a "true essence of humanity"? After a period of silence regarding the theory of alienation following the end of the systemic competition between capitalism and socialism, it has gained renewed relevance today. This volume discusses these recent studies, including those by authors like Alain Ehrenberg and Hartmut Rosa, against the backdrop of an assessment of older theories from Rousseau to Marx and Simmel to Herbert Marcuse.