Clint Twist has written more than 85 books for U.K. and U.S. publishers in the fields of science, nature, and history, and for readers of all ages. Some of his books include Charles Darwin and the Beagle Adventure, The Mythology Handbook (with Dug Steer), and The Oceanology Handbook.
We've read through this once and the boys have looked through it a bazillion times. The illustrations are fantastic. There is a small paragraph about each animal with a size comparison to a person and a small globe which shows where the animal is from.
It's a fun book to look through but you'd need more to really learn about a particular reptile or amphibian. A good general overview or jumping off place.