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Human language is one of the finest accomplishments of biological evolution. Much of our species’ success is fundamentally dependent on the capacity of language to generate ideas that allow us to escape from the immediate present or to describe events and phenomena that have never existed. Yet the origin and evolution of this powerful tool is quite mysterious. Other forms of animal communication bear so little resemblance to human language that it seems unlikely that any of them could be a precursor to spoken language. Pulling together various observations on the neurology of language, the sophistication and cross-cultural nature of sign languages, and the ability of apes to communicate with signs, Corballis argues that the origins of human language may lie in manual gestures, not in vocalization.