How did our modern picture of the universe come into being? Masters of the Universe tells this fascinating story in an unusual format that blends factual and fictional elements. It is based on a series of interviews that a fictional person conducted with leading astronomers and physicistsbetween 1913 and 1965. Among the interviewed scientists are giants such as Albert Einstein, Edwin Hubble, and George Gamow, but also scientists who are less well known today or not primarily known as cosmologists such as Karl Schwarzschild, Paul Dirac, and Svante Arrhenius. By following the interviews the reader gets a lively and "almost authentic" impression of the problems that faced this early generation of cosmologists. Although the interviews are purely fictional, a product of the author's imagination, they could have taken place in just the way that is described.They are solidly based on historical facts and, moreover, supplemented with careful annotations and references to the literature. In this way the book bridges the gap between scholarly and popular history of science.