As the book ends in 1990, it misses a lot. It only just starts to talk about the effect of CDs on the market. It briefly chats about DAT tapes, cassettes, 8-track, but in not much detail.
Steve Knopper's new book, "Appetite for Self-Destruction: The Spectacular Crash of the Record Industry in the Digital Age", appears to pick up from where Dennen's book left off [arstechnica review]
Much of the book details the rise of the CD and it's eventual dominance of the music market, and what the record companies did to take full advantage of the new format.
The later part of the book details Napster and what the record companies did, tried to do, and failed to do when digital music became the new format.
I'm mostly interested in the CD part, but the memory-lane aspect of the internet section should be fun.
I hope to pick up a copy soon.