This book is a journey down the alimentary canal with visits to experts in physiology as guides along with historical episodes to pioneers of the field. There is also a healthy dose of musings about how our cultural norms affect the way we think and behave regarding things we all know everyone has to do just to stay alive. I thought I was pretty dispassionate and would not be affected by the sense of disgust going along with the descriptions but there were times where I just had to stop the audio book for a while and return to it a day later. Beyond disgust there are accounts of painful and occasionally fatal conditions which veer into the lurid realm, although they are all in service of illustrating some point on the subject. There are also some odd characters the author interviews along the way whose quirks lighten up the mood with humor. Most of the science beyond the basics was pretty new to me, though by my age I have had some personal experience with procedures screening for illness at both ends. There are a few times when the author talks about medications which might no longer be current information after all the years since the book first came out. I thought it was a pretty good read as long as the ick factor didn't put a person off too much.