Our big brains, our language ability, and our intelligence make us uniquely human. But barely 10,000 years ago - a mere blip in evolutionary time - human-like creatures called Boskops flourished in South Africa. They possessed extraordinary features: forebrains roughly 50% larger than ours, and estimated IQs to match - far surpassing our own. Many of these huge fossil skulls have been discovered over the last century, but most of us have never heard of this scientific marvel. Prominent neuroscientists Gary Lynch and Richard Granger compare the contents of the Boskop brain and our own brains today, and arrive at startling conclusions about our intelligence and creativity. Connecting cutting-edge theories of genetics, evolution, language, memory, learning, and intelligence, Lynch and Granger show the implications of large brains on a broad array of fields, from the current state of the art in Alzheimer's and other brain disorders, to new advances in brain-based robots that see and converse with us, and the means by which neural prosthetics - replacement parts for the brain - are being designed and tested. The authors demystify the complexities of our brains in this fascinating and accessible book, and give us tantalizing insights into our humanity - its past, and its future.