The nature of time has long fascinated physicists and lay people alike. As an irresistible flow into which all events are embedded, time cannot be slowed or accelerated. It cannot be undone or turned back. In this marvelous text, Novikov describes how the thinkers throughout history have defined time and how these discoveries demonstrate that we may influence time's flow. He details the development of our views on time, from classical Greece to the modern day. This book describes how time flows in specific regions of the Universe, how it stops in black holes and splashes over the brim in white holes, and how time may convert into space and vice versa. The author explores time's genesis at the Big Bang and describes the current research on the physics of time. He details how recent discoveries indicate that time machine travel might be possible. Accessible to all, the engaging style and wonderful illustrations make this book hugely enjoyable to read. Igor Novikov is the author of Evolution of the Universe (Cambridge, 1983), Black Holes and the Universe (Cambridge, 1990), and E. Hubble, Life and Work (Cambridge, 1992). His extensive body of research begins in the former Soviet Union and his experiences add a unique touch to this book. Currently, he is the Director of the Theoretical Astrophysics Center in Copenhagen.