Amanda Petrusich emerges from one of the music world’s darker corners to share her barely believable findings. She describes collectors of pre-war blues records who are so focused in their pursuit as to make Dylan obsessives appear normal. Paramount Records of Grafton is a touchstone throughout, and this book does a good job with a truncated retelling of the label’s importance. Non-collectors might not believe that the level of competitive intensity described here could exist. Petrusich assures us that it’s not only real but, more importantly, that the remarkable music being preserved by these devotees is absolutely worth the effort.