"What power has love but forgiveness? By its intervention, what has been done can be undone. What good is it otherwise?" wrote William Carlos Williams, the philandering doctor-poet, in a poem to his wife Flossie. Williams' rather self-serving brief on behalf of forgiveness comes to mind when reading Mariah Burton Nelson's new book on the topic. Nelson, today an accomplished sportswriter, had a highly ambiguous, clearly exploitative relationship with her married 25-year-old athletic coach when she was 14. She was angry at him for two decades, but after a long series of telephone conversations, letter exchanges and in-person meetings with him, she felt herself able to forgive.

Are there limits to forgiveness? No, not really, writes Nelson in "The Unburdened Heart." Though she draws on Christian and Buddhist teachings, Nelson's own narrative is the most interesting part of the book; she reports on both sides, so the reader can to some extent decide independently whether "Bruce," the older man, is honest or as disingenuous as Williams in his pleas for absolution.