McCullough, whose last three books were academic, targets a general audience in this exploration of the human capacity for both revenge and forgiveness. Schooling readers in the basics of natural selection, McCullough argues that despite popular belief that revenge is a disease, both revenge and forgiveness have been adaptive for our species. Acting as a chatty tour guide through a labyrinth of game theory and studies of human and animal behavior, McCullough explains not only why humans seek revenge in some cases and forgiveness in others, but also delineates the neurological, psychological, social, cultural, and religious mechanisms behind these choices. McCullough approaches stories of extraordinary forgiveness with clear-eyed inquiry rather than misty-eyed reverence. What conditions, he asks, are most likely to lead to forgiveness instead of revenge? How can we create those conditions at a societal, even global level? While acknowledging that cycles of revenge seem unbreakable as they play out in a number of current conflicts, McCullough sees evidence of humanity’s collective will to break these cycles. Such innovations as restorative justice and truth and reconciliation commissions seem capable of provoking humanity’s hardwired impulse to forgive. Accessible but unsentimental, this book will appeal to all who wish to better understand forgiveness and how to engender it. (Apr. 4) (Publishers Weekly, February 11, 2008)