This introductory chapter provides an overview of the book's key themes. This book focuses on American science fiction films of the 1950s, many of which are fondly remembered, yet critically dismissed. It argues that it is through the intersection of past and present, of unresolved trauma superimposed upon present anxieties, that 1950s science fiction films acquire topical relevance within their historical context. Science fiction films from the 1950s are a belated response to the national trauma of World War II and the Korean War projected onto the unsettling experience of the Cold War. With much of the critical work on the Cold War aspects of the films already delivered by other scholars, this book will weigh in on the side of the argument that has, as yet, remained critically neglected—the side of past trauma: on World War II and the Korean War, and their troubling legacy in the first decade of the American Century.