From dancing squirrels to bashful gorillas to spiteful killer whales, Masson and coauthor Susan McCarthy bring forth fascinating anecdotes and illuminating insights that offer powerful proof of the existence of animal emotion. Chapters on love, joy, anger, fear, shame, compassion, and loneliness are framed by a provacative re-evaluation of how we treat animals, from hunting and eating them to scientific experimentation. Forming a complete and compelling picture of the inner lives of animals, assures that we will never look at animals in the same way again.