A benchmark publication, the first edition of the Phosphor Handbook, published in 1998, set the standard for references in the field. The second edition, updated and published in 2007, began exploring new and emerging fields. However, in the last 14 years, since the second edition was published, many notable advances and broader phosphor applications have occurred. Completely revised, updated, and expanded into three separate volumes, this third edition of the Handbook covers the most recent developments in phosphor research, characterization, and applications. This volume on ‘Fundamentals of Luminescence’ elucidates the theoretical background and fundamental properties of luminescence as applied to solid-state phosphor materials. The book includes the chapters that cover: Basic principles of luminescence, the principal phosphor materials, and their optical properties New developments in principal phosphors in nitrides, perovskite, and silicon carbide Revised lanthanide level locations and its impact on phosphor performance Detailed descriptions of energy transfer and upconversion processes in bulk and nanoscaled particles and core-shell structures Rapid developing organic and polymer luminescent materials and devices