For the beginner, full textbooks available in PDF format provide the foundational curriculum. Titles such as Vertebrate Paleontology by Michael J. Benton or The Vertebrate Body by Romer and Parsons are essential reading. While copyrighted recent editions require purchase or university access, many older editions or open-access educational modules are legally available. These documents offer a structured progression through geological time, explaining the evolution of fish, amphibians, reptiles, birds, and mammals.
Alfred Sherwood Romer was the titan of 20th-century vertebrate palaeontology. His original works are now in the in the United States. vertebrate palaeontology pdf
Not all PDFs are created equal. In vertebrate palaeontology, taxonomy changes rapidly. A PDF from 1995 might still call birds "reptiles" (phylogenetically, they are, but the terminology has shifted). Here is a checklist: For the beginner, full textbooks available in PDF
The BHL has digitized millions of pages of 18th, 19th, and early 20th-century natural history literature. Want the original description of Tyrannosaurus rex by Henry Fairfield Osborn (1905)? It is a free PDF on BHL. His original works are now in the in the United States
: Determining the evolutionary relationships between different species.