Definition of color appearance models and a framework for constructing them are covered in Chapter 10, where the CIELAB is discussed as an example of a simple color appearance model. Chapters 11 to 16 contain a presentation of more complex models, such as the one by Nayatani et al., Hunt, RLAB, ATD, LLAB, IPT, CIECAM97s, and CIECAM02. These chapters follow a general framework where the objectives and the methodology of the corresponding model are first described, followed by the definition of the input data to the model. This is followed by the presentation of the chromatic adaptation model and the opponent color dimensions utilized in the color appearance model. Calculation of appearance correlates (hue, lightness, brightness, chroma, and saturation) is discussed next. In many applications, it is necessary to use color appearance models in reverse direction, so the inverse of a model and the phenomena predicted by the model are presented next. Finally, a section explains the inadequacies of the described model and presents possible next steps. Currently, the CIECAM02 is considered one of the best available models that has drawn its strengths from other existing models. However, color appearance is an active area of research with new developments reported all the time.