The book accomplishes what it sets out to do, but it often relies on outside sources to make a metaphysical point, and where it delves into the musicality of it, relies on very pedestrian standard analysis to make the comparisons. The usage of a specific series of triads between a late work and the work of somebody else is interesting and all, but I'd much rather have seen more comparisons between his middle and late works. Most disappointingly of all, a fair amount of space is spent looking at his string quartet, which is excellent, but not really "late" and while space is spent on the Violin and Cello Sonatas, the Flute, Viola, Harp Sonata is missing, and very very little time spent dwelling on the possibilities of the 3 unfinished sonatas which would have followed it. The time spent on the Etudes was excellent, however.