Nearly a century before Mondrian made geometrical red, yellow, and blue lines famous, 19th century mathematician Oliver Byrne employed the color scheme for the figures and diagrams in his most unusual 1847 edition of Euclid’s Elements. The author makes it clear in his subtitle that this is a didactic measure intended to distinguish his edition from all others. This remarkable example of Victorian printing has been described as one of the oddest and most beautiful books of the 19th century.