Mary Roach wrote this book to explain what happens to your body if you donate it to science once you pass away. Since many do not know what science could use you for, Roach digs deeper and gets to the bottom of what experiments you are really used for. She describes constantly throughout the book how even though a cadaver does not have a beating heart or a thinking brain, it can still save so many lives because of the different experiments they are involved in, which is the overall message in her story. Many wonder if their body will be used for more than just an organ transplant, and the answer is yes; however, Roach does not merely answer this question. She goes into detail and defines the true meaning of donating your body to science. The author helps the reader understand that cadavers are purposeful in everything they do.