Several books chronicle attempts, most of them during the last 40 years, to teach animals to communicate with people in a human-designed language. These books have typically treated only one or two species, or even one or a few research projects. We have provided a more encompassing view of this field. We also want to reinforce what other authors, for example Jane Goodall, Sue Savage-Rumbaugh, Penny Patterson, Birute Galdikas, and Roger and Deborah...