This substantial book of letters selected by esteemed Colin McCahon scholar Peter Simpson shines a light on one of the most remarkable relationships in New Zealand art. The painter Colin McCahon and the librarian Ron O'Reilly first met in 1938, in Dunedin, when McCahon was 19 and O'Reilly 24. They remained close, writing regularly to each other until 1981, when McCahon became too unwell to write. Their 380 letters covered McCahon's art practice, the contemporary art scene, ideas, philosophy and the spiritual life. Dazzling in their range, intensity and candour, the letters track a unique friendship and partnership in art. The book is illustrated with 64 images, all discussed in the letters. Simpson's selection represents the first time these letters have been transcribed and collected in what is an act of great generosity to future scholars. It adds a new dimension to an understanding of McCahon and his career and is a rich and lively addition to any art lover's McCahon library. O'Reilly's son Matthew O'Reilly and McCahon's grandson Finn McCahon-Jones contribute insightful essays that round out the unique perspective the letters afford.