Since antiquity, people have searched for a way to understand the colours we see-what they are, how many there are, and how they can be systematically identified and arranged in some kind of order. How to order colours is not merely a philosophical question, it also has many practical applications in art, design, and commerce. Our intense interest in colour and its myriad practical applications have led people throughout history to develop many systems to characterize and order it. The number of colour order systems developed throughout history is unknown but ranges in the hundreds. Many are no longer used, but continue to be of historical interest. Despite wrong turns and slow progress, our understanding of colour and its order has improved steadily. Although full understanding continues to elude us, it seems clear that it will ultimately come from research in neurobiology, perception and consciousness. Color Ordered is a comprehensive, in-depth compendium of 165 systems, dating from antiquity to the present. In it, Rolf Kuehni and Andreas Schwarz present a history and categorization of colour systems, describe each one using original figures and schematic drawings, and provide a broad review of the underlying theory. Included are a brief overview of colour vision and a synthesis of the various systems.