For the past 12 billion years, galaxies have governed the Universe, bringing form to the firmament, light to the void. Each one a giant system of as many as hundreds of billions of stars, the galaxies are the building blocks of the cosmos, and through new data from modern telescopes - including the Hubble Space Telescope -we are discovering dizzying new facts about how they formed, how they evolve and what they are made of. This book acquaints readers with these facts and findings -and with what they can tell us about the lives of galaxies over cosmic time, from their emergence shortly after the Hot Big Bang to their ongoing gyrations and transmutations. Orienting us with an insider's tour of our cosmic home, the Milky Way, William Waller and Paul Hodge then take us on a spectacular journey, inviting us to probe the exquisite structures and dynamics of the giant spiral and elliptical galaxies, to witness colliding and erupting galaxies, and to pay our respects to the most powerful galaxies of all - the quasars. A basic guide to the latest news from the cosmic frontier - about the black holes in the centre of galaxies, about the way in which some galaxies cannibalize each other, about the vast distances between galaxies, and about the remarkable new evidence regarding dark energy and the cosmic expansion - this book gives us a firm foundation for exploring the more speculative fringes of our current understanding.