The twentieth century witnessed the development of astrophysics and cosmology from subjects which scarcely existed to two of the most exciting and demanding areas of contemporary scientific inquiry. In this book, Malcolm Longair reviews the historical development of the key areas of modern astrophysics, linking the strands together to show how they have led to the extraordinarily rich panorama of modern astrophysics and cosmology. While many of the great discoveries were derived from pioneering observations, the emphasis is upon the development of theoretical concepts and how they came to be accepted. These advances have led astrophysicists and cosmologists to ask some of the deepest questions about the nature of our Universe and have pushed astronomical observations to the very limit. This is a fantastic story, and one which would have defied the imaginations of even the greatest storytellers.