Time Life book from 1972. I had expected the biological anthropology in this book to hopelessly out dated, but surprisingly many of the basic theories of human evolution contained in its pages remains current. The most amusing frustration of author Maitland Armstorng Edey in the book was the lack of a more complete australopithecine skeleton to study, which of course would be discovered two years later and is now known today a "Lucy." (Named after the Beatles song "Lucy in the Sky with Diamonds") I highly recommend Donald Johanson's Lucy: The Beginnings of Humankind if you are interested in the tale of how Australopithecus Afarensis was stumbled upon.
The Missing Link names Australopithecus Afarensis as the bridge between modern humans and our primate relatives. The bones of these animals are incredibly ancient, in the neighborhood of 4.4 million years old, and remarkably already bipedal. In fact walking upright on two legs seems to predate both tool use and brain size by untold millennia. The book also reviews early DNA studies which indicate that the chimpanzee has 98% of the same genetic code as a human being.
That 2% variance accounts for our conscience, morality, art, science, religion, philosophy, history, and what we consider the human estate.
Its beautiful how the data from sience in the 60's are still so valuable to produce aw moments of understanding the nature and the nurture of humans. And most important, how they intertwiend and inform each other in that magnificent positive feedback process.