"Nearly a century before Mondrian made geometrical red, yellow and blue lines famous, 19th-century mathematician Oliver Byrne employed the colour scheme for his 1847 edition of Euclid's mathematical and geometric treatise Elements. Byrne's idea was to use colour to make learning easier and 'diffuse permanent knowledge.' The result has been described as one of the oddest and most beautiful books of the 19th century." This book is a facsimile edition of Oliver Byrne's 1847 version of Euclid's 'Elements', in which colourful diagrams and symbols are used instead of letters to illustrate geometric propositions. It is simultaneously a work at the intersection of mathematics, typography, and visual art, with a focus on the primary colours red, yellow, and blue and a layout that anticipates later design movements. The content covers the first six books of Euclid's classic work, concentrating on plane geometry, constructions, and logical reasoning. Oliver Byrne (1810-1880) was a 19th-century mathematician and engineer, famous for his visually striking 1847 edition of Euclid's 'Elements', where he used colour as a pedagogical tool. Werner Oechslin (born 1942) is an art historian and mathematician, acting as editor of this reissue; he is known for his work on architectural history and the history of science.