Virtually every human society shares a fascination with our deep past. For many of us, the study of human origins and evolution from our ape-like ancestors (also called paleoanthropology) is one of the most exciting scientific fields because it investigates the origin, over millions of years, of the universal and defining traits that make our species what it is. It is the science that shines light on the question, "What does it mean to be human?"

In the pages that follow we will discuss the fossil record of the lineage of early humans as we know it today. Using the casts in the National Collection at the Smithsonian Institution's National Museum of Natural History, we will follow the evolution of our small branch of the Tree of Life.