HOUSE OVERSIGHT 025148 technical expression for this is time-reversal symmetry. This basic property seems to be entirely at odds with the pronounced unidirectionality of experienced time. In fact, there are several arrows. "Until recent work by myself and my collaborators Tim Koslowski and Flavio Mercati, essentially only one proposal had been made—in well over a century—to explain why, despite the time-reversal symmetry of all the laws of nature, these pronounced arrows of time exist, and always have existed, throughout the observable universe. As I explain in The Janus Point, this sole explanation is a manifest stop gap and satisfies no serious scientist. "This has been dubbed the past hypothesis. However, it is not in any sense an explanation that follows from the structure of the law and does not lead to any new prediction. It is an admission of defeat: Modern science fails to explain the most profound aspects of our existence. "The Janus Point is clearly timely because it is about a set of very simple ideas and insights that have the potential to solve one of the deepest and longest-standing problems in physics. Everyone is interested in time and its numerous puzzling aspects. Proof of that is the success of my earlier book The End of Time, which is still selling more than sixteen years after its publication. Some of the ideas conjectured in that book are, in fact, realized in the model now proposed. "For readers, The Janus Point tells the fascinating story of one of the greatest mysteries in science and what looks to be its unexpected and, in principle, remarkably simple solution. More than most books in popular science, its subject resonates profoundly with the reader. Nothing touches us more intimately than the drama of birth, life and death." JULIAN BARBOUR, an independent researcher, is currently visiting professor at the University of Oxford. He has devoted significant time and effort to issues that lie at the foundations of science,