This classic is the best single volume reference for the identification of fossil invertebrates. It was a staple for working field geologists for decades. This is because the identification of "index fossils" was, and is, the handiest way to date strata in the field.
The book is organised by phylla: Protozoa, Porifera, Coelenterata, Echinoderma, Annelida, Conodonts, Bryozoa, Brachiopoda, Mollusca, and Arthropoda. There are also sections on fossil plants and miscellaneous objects of probable organic origin. Everything is illustrated by crisp, sharp, photographic plates, clearly indexed to the corresponding text.

By today's micropaleontological standards, the Protozoa section is pretty thin, but otherwise this is still a very useful volume.