Truth used to be based on reason. No more. What we feel is now the truest source of reality. Despite our obsession with the emotive and the experiential, we still face anxiety, despair, and purposelessness. How did we get here? And where do we find a remedy? In this modern classic, Francis A. Schaeffer traces trends in twentieth-century thought and unpacks how key ideas have shaped our society. Wide-ranging in his analysis, Schaeffer examines philosophy, science, art, and popular culture to identify dualism, fragmentation, and the decline of reason. Schaeffer's work takes on a newfound relevance today in his prescient anticipation of the contemporary postmodern ethos. His critique demonstrates Christianity's promise for a new century, one in as much need as ever of purpose and hope.