Now in its 4th edition, this classic text for senior undergraduates and beginning graduate students in physics and astronomy presents a wide range of astrophysical concepts in sufficient depth to give the reader a quantitative understanding of the subject. The book outlines cosmic events, emphasizing physical concepts, but does not portray them in detail. Rather, it provides a series of astrophysical sketches exploring the scope of modern astrophysics and elementary problems concerning the scale of cosmic objects and events, and develops the basic physics needed to answer these questions, using specific astronomical processes as examples. The second half of the book enlarges on these topics and shows how we can obtain quantitative insights into the structure and evolution of stars, the dynamics of cosmic gases, the large-scale behavior of the universe, and the origins of life.