This book should be understood in the context of the first Life Through the Ages, written and illustrated by Charles Knight around 1950. Knight was perhaps the greatest illustrator of the prehistoric to have ever lived, despite being legally blind. Beginning his career in the 1890s, he was the first artist to understand painting (use of color, composition, shading, etc.), animal anatomy, and paleontology at the same time. Before 1900, he was depicting therapod predators leaping and rolling around in combat, something that was very rare until the late 1970s. At the end of his career, after he painted all the famous murals at all the greatest Natural History museums, he created Life Through the Ages, a series of prints and accompanying descriptions.
Witton is my favorite living illustrator of deep time. From the beginning, he always had the most interesting things to depict, and his accuracy to plausible anatomy and the fossils was second to none, but over time his digital painting skill has increased to the point that he is now one of the best in the field at that, too. This is his take on Knight's concept, about 75 full page color illustrations on the right hand page, and a page full of text about them on the facing left hand page.
While there are a lot of dinosaurs and pterosaurs (Witton's specialty), some of the most fascinating to me were the illustrations of mammals and of bizarre pre-dinosaur life forms, which I have not seen depicted as often, and rarely well. A stand out is the last land whale (georgiacetus, I think?), which looks like something between a walrus and a particularly vicious dolphin. The pages are varied in subject matter, color scheme, and presentation, and there were tons of small facts I didn't know. My only complaint is that the reproductions (though high quality, sharp, and colorful) do not show contrast as well as the computer screen on which they were created so many are a little dark and muddy.
As an aside, I've been playing with Stable Diffusion for generating illustrations and one thing it is just terrible at is dinosaurs-- almost as bad as it is at fingers. Even if some future version can get their general appearance right, it will be quite difficult to get them able to incorporate the latest scientific findings as Witton does. I think his employment is secure for a while yet.