Existentialism: An Introduction has established itself as the most comprehensive and accessible book on the subject available. In this fully revised and expanded second edition, Kevin Aho draws on a wide range of existentialist thinkers from both the secular and religious traditions, adding a wealth of new material on existentialism's relationship with Marxist thought and its impact on feminist phenomenology and critical race theory. Chapters center on the key themes of freedom, authenticity, being-in-the-world, alienation, and nihilism. Aho also addresses important but often overlooked issues in the canon of existentialism, including the role of embodiment, existentialism's contribution to ethics, political theory and environmental and comparative philosophies, as well as its influence on the allied health professions. By tracking its many and significant influences on modern thought, Kevin Aho shows why existentialism cannot be easily dismissed as a moribund or outdated movement, but instead endures as one of the most important and vibrant areas of contemporary philosophy. Existentialism remains so influential because it forcefully deals with what it means to be human and engages with fundamental questions such as "Who am I?" and "How should I live?" Existentialism: An Introduction is the ideal text for upper-level philosophy students and for anyone interested in the movement's key figures and concepts.