So I understand the lure of the pun with a book like this, but there are seriously four other books with almost exactly this same title. The gross topics are certainly popular, and this book rides that wave.
The facts in this book are pretty interesting, though. I thought her approach to scatology was very thorough, and browsable. In fact, this isn't really a book about poop at all--it's a complete survey of animals using poop as the unifying topic. Just as another science book might focus on habitat or food, this one cuts through the animal world with the one topic of focus.
Zombie ants and animals that eat poop are two favorite pages. I enjoyed how long the book was, without losing its high interest--it's really very thorough.
Sources: Not so good. Cusick gives a handful of books, but no evidence of her research. Without clear sourcing of the research, and no evidence of her own qualifications I want more connection to the science and research world of coprology.
What does this book do that an internet search wouldn't? A lot of the facts in the book are right there on wikipedia, but this book's cachet is its volume of facts, the number of animals it works with, and the way this helps diversify and add interest to the topic. There isn't an easy-to-find web site that covers this topic.