Publisher Summary Modern ceramics are a very diverse group of materials with widely varying physical properties that can be adapted to many technological needs. The basic science of advanced ceramics is approached in three steps. First, the major classes of ceramic materials are introduced and their crystal structures and crystal chemistry described. Then, the various models for chemical bonding in ceramic compounds are briefly outlined. The third step is to relate physical properties to crystal chemistry and crystal structure. The properties depend on crystal structure, on the electronic structure of the individual ions that make up the structure, and on the chemical bonding within the structure. Structures are determined in large part by ratios of the atomic constituents and by ionic radii. Bonding is a function of the collective interaction (or lack of interaction) of the outer-shell electrons with each other. There are three main models that can be applied to chemical bonds in ceramics and each has its own theoretical structure. These are the classical electrostatic model, augmented by crystal field theory, for ionic compounds; the molecular orbital model for covalent compounds; and the band model for semiconductors and metals.