This book is about the true heroes of pop music that usually stay in the shadows — producers and songwriters. Surprisingly, most of the top pop hits in 90s and 00s were written by just several people. Some of the monsters like Sweden Deniz PoP and Max Martin (which are not real names of cause) proved to be a really big hit machines.
Max Martin alone is credited for 22 Billboard's number 1 hits. Those include artists from Backstreet Boys to N'Sync, all the way down to Maroon 5 and Taylor Swift. Personally I don't really fall for such kind of music, but that incredible productivity in hit making makes me respect those men tremendously and the work they do.
This book is very entertaining in how it tells a story of the evolution of the pop music and the people behind it. Musical styles keep changing, but as it happens this trajectory is spiral. Pop music tends to oscillate between the "pure" pop and the "edge" pop, when the tired audience is more readily embrace the new styles like hip-hop or black R'n'B, or grunge, or indie. Which in their turn keep changing to become more softer and eventually the circle is closed.
Another thing that stands out to me is that sort of heredity of pop music in a sense that every producer teaches the next big producer. So Deniz PoP has a protegee Max Martin, then Max Martin protegees Dr. Luke, then Dr. Luke protegees the next big thing and so on... And if Deniz started with Ace of Base, Dr. Luke wrote songs for Kasha. So you kinda can see the Sweden DNA in modern US pop.