The origin of our capacity for language is a complex topic, requiring input from many disparate fields, from linguistics to paleoanthropology. Specialists in any one field are often unfamiliar with the evidence from other relevant disciplines. I perceive a need for an integration of knowledge from all relevant fields, outside as well as inside linguistics, in a single work. My purpose in writing this book is to bring together the material needed for such an integration, and to take the first steps towards the synthesis needed for a thorough understanding of the evolution of language.