I think the ethos of this book is excellent, it is encouraging people to see those animals that are facing extinction whilst raising awareness of them and touching on the reasons for they are under threat.
Each animal has a high quality image, a map of where to find them and text about them and their history.
They are grouped by geography, which is logical based on the premise that you will attempt to see these animals in the wild.
I guess that leads to my only minor concern with the book in that it doesn't give you any information about where you may be able to see some of them in captivity. It would be nice to see all 100 in the book, but it unlikely given the diversity of them.