A third report on the gorilla who has been taught an extensive sign language. Dr. Francine Patterson's accounts, Koko's Kitten (1985) and Koko's Story (1987), were illustrated with color photos; the use here of Cannon's precise, delicately drawn color illustrations allows more expressive interpretation but less of a sense of Koko's reality. McNulty, who often writes about science topics for children, here reports on her own visit to Koko in 1976; her clear, pleasant text conveys the apprehension and delight of making the gorilla's acquaintance, but doesn't significantly add to the information in Patterson's books. Still, a good supplemental title on a high-interest topic.