Most scholarly speculation on the origin of human language has centered around speech. However, the growing understanding of sign languages on human development has transformed the debate on language evolution. David F. Armstrong’s new book Show of Hands: A Natural History of Sign Language casts a wide net in history and geography to explain how these visible languages have enriched human culture in general and how their study has expanded knowledge of the human condition. Armstrong addresses the major theories of language evolution, including Noam Chomsky’s thesis of an innate human “organ” for language and Steven Pinker’s contention that there is language and not-language without any gradations between gesture and language. This engrossing survey proceeds with William C. Stokoe’s revival of the early anthropological cognitive-linguistic model of gradual development through the iconicity of sign languages. Armstrong ranges far to reveal the nature of sign languages, from the anatomy of early human ancestors to telling passages by Shakespeare, Dickens, and Pound, to the astute observations of Socrates, Lucretius, and Abbé de l’Epée on sign communication among deaf people. Show of Hands illustrates the remarkable development of sign languages in isolated Bedouin communities and among Australian indigenous peoples. It also explores the ubiquitous benefits of “Deaf Gain” and visual communication as they dovetail with the Internet and its mushrooming potential for the future.