[De Waal] makes an excellent case for the hypothesis that there is no emotion in our human psyche that we don't see in our closest relatives - and, in fact, in intelligent animals of all kinds, especially mammals and large-brained birds ... A convincing book, and De Waal [is] an excellent observer of primate behaviour [and] immensely knowledgeable... a window into chimps' lives, and a looking glass for our own