This is an essential practical guide to how colour works in light. Written from the perspective of a theatrical lighting designer, it discusses how to see colour, how to construct effective lighting palettes, and how to make use of both colour filters and colour-mixing LED fixtures to create compositions that work well with scenery and costumes to tell compelling stories. We are presently at the leading edge of a revolution in theatrical lighting, redefining how it can be used to create and communicate. Todays LED-based additive colour-mixing fixtures require new methodologies and new ways of thinking, and the book directly addresses this technologys potentials and challenges. But underpinning lightings many recent technological changes is the fundamental language of colour that artists have worked with since the birth of humanitys artistic urges. More saturated vs. less, warmer vs. cooler, more green vs. more magenta, recessive vs. dominant -- the bedrock language of colour