What are colors, actually? Are they given in the world or products of subjective consciousness? What kind of thing do we refer to when we label something as "red," "green," or "blue"? The debate about the status of colors is one of the most interesting and open discussions within philosophy and also intersects with insights from cognitive research and neuroscience. Since Descartes, questions regarding color perception and the ontology of colors have been at the center of the discussion. This volume provides a systematic overview of current and historical color theories from various fields of knowledge. Fascinating parallels as well as breaks in the theoretical engagements with the phenomenon of colors emerge.