Maybe a guide could be created of The struggle for a proletarian party by James P. Cannon. Many of the methods of the contemporary Trotskyist groups (papersales, method of organisation, way of handling internal disagreements, etc, etc) can be traced in its origins to this work. Before it, many of said methods seems to be "missing" or simply non-existent. So, James P. Cannon's work can be said a defining the Trotskyist strand of communism for at least a part.