There is no more profound, enduring, or fascinating question in all of science than that of how time, space, and matter began. Now John Barrow, who has been at the cutting edge of research in this area and has written extensively about it, guides readers on a journey to the beginning of time, into a world of temperatures and densities so high that we cannot re-create them in the laboratory. With new insights, he draws us into the latest speculative theories about the nature of time and the inflationary universe, explains wormholes, showing how they bear upon the fact of our own existence, and considers whether there was a singularity at the inception of the universe. Here is a treatment so up-to-date and intellectually rich, dealing with ideas and speculation at the farthest frontier of science, that neither novice nor expert will want to miss what Barrow has to say. He shows how scientists, by exploring crucial points of contact between the behavior of matter during its early history and the observed structure of the universe today, came to understand more fully all the entities in the universefrom elementary particles to great clusters of galaxies.