The 1938 recipient of the Governor General's Award for Literary Merit is John Murray Gibbon's Canadian Mosaic : The Making of a Northern Nation
Gibbon uses this book to prove his thesis that Canada is made from a variety of peoples of different cultures and national origins, who together, form a strong, cohesive country. Gibbon's book very much serves as a counterweight to Nazi theories of racial ideology and purity. Gibbon uses the terms of his contemporaries to present a positive perspective of racial diversity. He traces the origins of nearly every wave of European immigration to Canada. The language is clearly racial in nature, but Gibbon uses it to argue for the merits of a heterogeneous society.
I admire Gibbon's thesis, but his writing works better as a concept than as a book. He proves his theory that Canada is a diverse country made up of numerous generations of European immigrants (Gibbon focuses almost exclusively on people of European origin). However, stylistically, he does so by often listing numerous Canadians of various national origins. In other words, this book is effectively a series of lists of notable immigrants to Canada. It provides sufficient evidence, but I don't know that I would categorize this approach as deserving of literary merit.
Those looking for a pro-diversity racialist argument from the 1930's will find much interesting about Gibbon, however those looking for a truly great work of Canadian nonfiction should look elsewhere. This is very much a period piece, and while I am hesitant to criticize it according to the standards of today, I imagine that even to its contemporaries it worked better as a compilation than a unified literary work.