Capturing the excitement and accomplishments of X-ray astronomy, this second edition now includes a broader range of astronomical phenomena and dramatic new results from the most powerful X-ray telescopes. Covering all areas of astronomical research, ranging from the smallest to the largest objects, from neutron stars to clusters of galaxies, this textbook is ideal for undergraduate students. Each chapter starts with the basic aspects of the topic, explores the history of discoveries, and examines in detail modern observations and their significance. This new edition has been updated with results from the most recent space-based instruments, including ROSAT, BeppoSAX, ASCA, Chandra, and XMM. New chapters cover X-ray emission processes, the interstellar medium, the Solar System, and gamma-ray bursts. The text is supported by over 300 figures, with tables listing the properties of the sources, and more specialized technical points separated in boxes.