This book, first published in 1991, tells the story of how astronomy and physics work together to unravel many mysteries of stars and nebulae. Stress is laid on a non-technical description of how an understanding of these objects is obtained, not on just a mere review of facts. After a succinct, non-mathematical excursion into the principles of radiation and atomic structure, the text explains in simple terms the physical processes at work in stars and gaseous nebulae. A survey of masses, dimensions, luminosities, temperatures and chemical composition of stars is followed by an exploration of their interiors and how stars generate energy. An account of the exciting new field of high energy astronomy and the origin of cosmic rays is given at the end of the book. This is the ideal introduction for physics and astronomy students to the important field of modern astronomics. It should also appeal to amateur astronomers and the reader interested in the life history of a star.