I really like medical mysteries and stories of medical deduction and this one was great. The general topic is the history of how we learned about prion diseases but it goes over a lot of different stories including a family in Italy who seems to have a bizarre hereditary disease and tribespeople in New Guinea who were thought to be cannibals and have gotten a mysterious disease from that practice. And then the author has his own disease that he briefly mentions in the course of talking about this disease which humanizes the whole thing. I really enjoyed this book, even with its creepy cover.