Images of the real world are formed by visible light being scattered by surfaces and volumes. The goal of global illumination methods is to simulate the path of light in an environment through the image plane in order to compute realistic images. Not all applications require the accuracy attainable with global illumination methods, and not all global illumination methods are good for all possible lighting effects. In this course the audience will be given a vocabulary and taxonomy for understanding global illumination. Insight into the basic methods will be provided using comparison to physical experiments. The target audience includes: people who are new to graphics who want to be generally informed, people who teach graphics courses but specialize in some other area of graphics, and/or people who think they may need global illumination for their application and want to understand how these methods differ from other rendering techniques.