This tutorial is written to help engineers tasked with designing illumination optics determine where to start, which methods and approaches to use, and how to gain insight into the nature of the problem at hand. Good illumination design uses patterns from both non-imaging optics (such as compound parabolic concentrators) and imaging optics (such as lenses), often in combination, to produce optimal solutions. These chapters provide readers with a toolbox consisting of a coherent theoretical background, a description of important optical elements and their function, and several design methods. Typical examples are described to illustrate how an experienced optical designer approaches problems, plays with concepts, and arrives at solutions.