De Waal F. (1996) Good Natured: The Origins of Right and Wrong in Humans and Other Animals. Cambridge MA: Harvard Univ Press.
A charming mix of 1st person writing with the supporting data and references tucked to the rear in case you should want it. There are personal glimpses of his reactions to other evolutionists. He moves gently from apes, monkeys, dolphins, elephants, and other creatures. There's some recent history of biology, ethology, and studies of animal morality. He shows the continuity of human and animal life by illustrating in animals qualities once thought restricted to mankind.
He presents examples of succorance, affective contagion, attachment, and grieving in many species. Elephants will sometimes cover the body of a dead peer with dirt and grass. Whales appear to be more mutually protective than many primates. Further, experimental cognitive challenges to chimps and orangutans strongly suggest self-awareness, deception of several kinds, and sympathy (not only an understanding of another's needs but also some active behavior to meet them).
There's a hidden issue for cognitive therapists who have taught us for two decades not to mind read one another. Evolutionary Psychology suggests that not only can people accurately read each others intentions such as deception, approval, sympathy, pain, anger, and affection, but we can also read them in other creatures and perhaps with some accuracy. There are even some hints that our ape kin (chimps, gorillas, and orangutans) can read them in us.
This is a complex and touching book that should become a good friend. I strongly reacted to a photo of a young elephant with the skull of another, detusked elephant in her trunk. The caption says, "Fifteen months after having lost her mother, Agatha still regularly returns to the fatal spot to gently turn and feel her mother's skull." There are many such examples.