This book brings together the many fascinating theories of our universe, from the earliest philosophies to today's cutting-edge scientific discoveries. Collectively it aims to explain the origin and evolution of the universe at large, the processes by which planetary systems form, and the chances of life being ubiquitous beyond our own planet. Disputes and fierce competition between eminent scientific figures is discussed, and developments in optical telescopes, radio telescopes, X-ray telescopes and a variety of satellite instruments which help us to learn more about the universe are followed. The work, knowledge and, in some cases, falibility, of historical figures is investigated, along with Edwin Hubble's work on nebula and expansion, Einstein's theory of relativity, the extensive theories on supermassive black holes conducted throughout the 20th and 21st centuries, the production of radio energy by some galaxies, haloes, dark matter, and the perplexing possibilities of infinity. Written for those with good scientific knowledge and lay people alike, this book is a fascinating exploration of the complexities and astonishing depths of our universe, as well as a glimpse of how much we still have to learn about why and how it exists.