In the spring of 1918 Lawren Harris and J.E.H. MacDonald, two members of the soon-to-be-formed Group of Seven, met in the Studio Building in Toronto. Their friend Tom Thomson had died in mysterious circumstances the year before and, together, they determined to establish him as one of Canada's great artists. Most of his paintings and sketches were stacked up in the studio, and they decided on a plan. They would select the best, mark their comments on the back of these works, and make sure they got into Canada's most prestigious public and private collections. These two great artists choose to honour Thomson in this way because they had been his mentors and friends. Along with other painters such as A.Y. Jackson, they had taught him about current art movements in Europe and coached him in painting techniques. Thomson learned quickly, and, in the three or four years before his death, he combined this knowledge and these skills with his own prodigious talent and intimacy with nature. His friends recognized that, in many ways, they would never be able to paint like him. The pupil had become the master - and Harris and MacDonald, together with Jackson, wanted to be sure that he would be recognized and remembered. In later years, collectors such as Ken Thomson and Robert McMichael assembled their selection of Thomson masterpieces, as did private collectors today. Art historian Joan Murray has constructed this treasury with all these choices in mind - and written an insightful commentary on each one. Knowing the story that lies behind Thomson's greatest works helps us to view these paintings with new insight and appreciation. We understand what makes these works special.