For all functions of living and working, good lighting is essential. This does not just concern the amount of light required to ‘perform the task of the eye’, but also the level of visual comfort. It is especially important to prevent major differences in brightness in the field of vision. Furthermore, the lighting must be sufficiently divided or, rather, properly focussed if a certain object must be accentuated. This chapter deals with all basic variables and provides directions for dealing with daylight and artificial light.