When I reviewed Sixsmith’s Russia I mentioned that it was sometimes classified as a textbook, even though the narrative style made it much easier to read than a traditional history text. Unfortunately, this book is the opposite of that. Even though the book is admittedly dry at times and full of nerdy digressions, it is still a worthwhile endeavour for zealous music fans, even if just as a collection of various philosophies and studies of music. 
The biggest thing going for the book is the author. Dr. Nolan Gasser is “the chief architect of Pandora Radio’s Music Genome Project” as well as a musician. This gives him the credibility and clout he needs in order for the reader to trust his myriad rabbit trails. They typically go something like, “Here are some interesting ideas about music lovers within the electronica genotype. They like steady rhythm and ambience. But first, a 400 year history of the cultural implications of drumbeats and the need to be part of a tribe…” And then there’s that rabbit hole with three different subtrails based on different schools of thought.
Gasser reads the audiobook himself and is gleefully aware of his nerdiness, so a lot is forgivable. If you go with the 39-hour audiobook version, I would recommend turning up the speed to about 1.35x to get Gasser to what is a normal pace of conversation in average social circles. For areas of the book full of musical examples, turn it back down to 1x. Those examples are often real recordings from major artists, which is a big draw of the audiobook versus the print book.If you’d rather have the print book, the hardcover is attractive and laid out well. That is a pro if you want go back and reread certain sections or theories to crystallize your understanding of a certain idea.
No matter which version you get, there’s a companion website worth checking out. It includes things like musical charts, playlists from the book, and some ongoing studies of Gasser’s mentioned in the book.
While 40 hours did seem long, Gasser is true music lover and therefore a great hang if you’re a kindred spirit. Just think of the book as a fun audit of a college course, or a series of hangs with a friend at the record store.