"Version: 20151101"--Title page verso."A Morgan & Claypool publication as part of IOP Concise Physics"--Title page verso.Includes bibliographical references.Preface -- 1. Observational background -- 1.1. Distances -- 1.2. Stellar brightness and luminosity -- 1.3. Colors -- 1.4. Spectroscopy -- 1.5. Color-magnitude diagrams -- 1.6. Stellar masses -- 1.7. The mass-luminosity relation for main seq…