The study of stars and their spectra is central to an understanding of classical and modern astronomy. The principal tool for investigating the nature of stars is to observe and interpret their spectra. In this lucid book, James Kaler clearly explains the alphabet of stellar astronomy - from the cool M stars to hot O stars - and tells the story of the evolution of stars and their place in the Universe. Before embarking on a fascinating voyage of cosmic discovery, we are introduced to the fundamental properties of stars, and how they can be categorised. Next, the structure of atoms and the formation of spectra is discussed, as a prelude to a full description of the spectral classification itself. The heart of the book examines each star type in turn and explores their spectra in detail. Notable discoveries and features related to each class sustain the story. There is also a review of unusual stars that cannot easily be classified. Finally, the book closes with a skilful integration of all the data - tracing the paths of birth, life and death of stars on the Hertzsprung-Russell diagram. This book is based on a widely acclaimed series of articles on stellar astronomy which appeared in the magazine Sky and Telescope. It provides an invaluable introduction for observers and students.