I bought this encyclopedia for my son's 7th birthday. It was his favorite gift, hands down. He still takes it with him everywhere. The book is full of pictures and lots of neat facts that are enough to challenge a 7 year old, but concise enough that he can read them simply. The book is split up into different categories of animals: Mammals, Creepy Crawlies, Birds, Reptiles, etc. Then each category has pages for different types of that creature. For example, mammals has ocean mammals, horses, marsupials, flying mammals, etc. The pictures are wonderful, and as I said, the amount of text is just right. I am so glad I bought this. My son is happy to sit for hours on end looking at this book. I highly recommend it for any animal loving child.