The economic cost of retardation measures in the billions each year and the human cost is incalculable. However, many forms of retardation can now be prevented medically and much is now known about how to help the retarded lead more normal and satisfactory lives. In Mental Retardation, Dr. Robert Edgerton provides an extraordinarily useful and humane guide to this new knowledge in the brief and readable format that has become a trademark of the Developing Child series.

The book begins with a clear review of what is known about the causes of retardation, ranging from genetic abnormalities to prenatal infection, malnutrition in early childhood, environmental toxins (such as lead paint), and poverty. Edgerton shows how many of these problems can be avoided by genetic counseling, improved prenatal care, and the elimination of environmental hazards. But he also goes on to consider the questions that inevitably arise when prevention fails and family and society must cope with a retarded child: What is the impact of the child on the family? Is care within the family preferable to institutionalization? How can schools best educate the retarded? Is "mainstreaming" sensible? And how far can the retarded adult go towards normal patterns of work and social life within the community?

Mental Retardation makes it clear that many of the problems of retardation are caused by the misunderstanding and intolerance of a society like our own, which places extraordinary emphasis on mental ability and its measurable manifestations: school achievement and IQ. It is just this sort of intolerance and misunderstanding that this book does so much to dispel.

Somewhere in Africa, more than a million years ago, a line of apes began to rear their young differently than their Great Ape ancestors. From this new form of care came new ways of engaging and understanding each other. How such singular human capacities evolved, and how they have kept us alive for thousands of generations, is the mystery revealed in this bold and wide-ranging new vision of human emotional evolution.

Mothers and Others finds the key in the primatologically unique length of human childhood. If the young were to survive in a world of scarce food, they needed to be cared for, not only by their mothers but also by siblings, aunts, fathers, friends—and, with any luck, grandmothers. Out of this complicated and contingent form of childrearing, Sarah Hrdy argues, came the human capacity for understanding others. Mothers and others teach us who will care, and who will not.

From its opening vision of “apes on a plane”; to descriptions of baby care among marmosets, chimpanzees, wolves, and lions; to explanations about why men in hunter-gatherer societies hunt together, Mothers and Others is compellingly readable. But it is also an intricately knit argument that ever since the Pleistocene, it has taken a village to raise children—and how that gave our ancient ancestors the first push on the path toward becoming emotionally modern human beings.