This book gives an introductory treatment of the optical properties of solids. The fundamental principles; of absorption, reflection, luminescence and light scattering are discussed for a wide range of materials, including crystalline insulators and semiconductors, glasses, metals, and molecular materials. Classical and quantum models are used as appropriate, and the phenomena are well illustrated using recent experimental data. A particular feature is the inclusion of many new topics that have come to the fore in recent years and have not previously been covered in other solid state texts at this level. Examples include semiconductor quantum wells, organic semiconductors, vibronic solid state lasers, and nonlinear optics. The book is primarily written for physicists, but it will also be useful for electrical engineers, materials scientists, and physical chemists. The subject material is developed in a tutorial style, and includes worked examples, exercises and chapter summaries for revision.