In 1880s Britain, philosophers developed what would become a half-century obsession with time. Back then, time was widely held to be unreal. By the 1920s, it was widely held to be real. This sea change was gradual but sweeping. Early time realists focused on defending the reality of time. From around 1900, they began asking fresh questions about the nature of time, all loosely concerned with its dynamicity-its 'moving on'. Are the past and future real? Is time fundamentally an 'A-series' or 'B-series': about past, present, and future, or earlier and later? Does time have an intrinsic direction? These questions are still widely debated today. Real Time investigates the reinvention of time realism and follows the emergence of these new, in-house realist debates. Thomas argues these questions are not perennial but rather deeply rooted within this historical context. The story unfolds through anti-realist figures such as F. H. Bradley and J. M. E. McTaggart, and realists such as Samuel Alexander, Hilda Oakeley, G. E. Moore, Bertrand Russell, Karin Costelloe-Stephen, C. D. Broad, Alfred North Whitehead, and Arthur Eddington. These figures returned to time repeatedly across their careers, grappling with it in a variety of ways. Many placed time at the heart of their philosophies. Through their published works and unpublished archival correspondence, Thomas shows how time became one of the problems of early twentieth century philosophy-and those vintage ideas still shape ours today.