This review is for the whole series.
These books have been the backbone of my classification of animals unit for the last two years. They're structured beautifully, beginning with the taxonomy chart, and then showing the breakdown of the various orders within each class.
The rest of the book then takes a closer look at each of the orders and what makes them different from the other animals in that class.
Plus the pictures are lovely and frequently come with captions containing fun or interesting facts.