I expected to enjoy this book, but I found it lacking. I appreciate Roach's attempts to bring humor to topics many feel uncomfortable with, but it seemed that there was too much effort in this book. I was hoping a better balance between scientific facts and shocking and funny stories for each topic. There was too much emphasis on the shock value of some stories, and not enough scientific information for my taste. With the greater emphasis on stories, the different topics in the book seemed unconnected.
I did not engage with this book, and was rather disappointed after enjoying her book Stiff: The Curious Lives Of Human Cadavers. In Stiff, humor was used to open readers up to what could be a difficult and taboo topic. Here, I felt it was all humor and that I learned little beyond a few odd facts. If you have not read Roach's books before, I would start with a different book. Read this only if you are a great fan, or have a great interest in the topic.
I would recommend reading one of her other books.