I grow wary whenever authors send their sleuths on exotic assignments. (Is this trip absolutely necessary -- or just an excuse to write off a vacation?) This unkind suspicion doesn't stick to Kathy Reichs, like the protagonist of her ghoulishly entertaining novels a forensic anthropologist for the Province of Quebec and the State of North Carolina who is often called to far-off scenes of unspeakable horror. One humanitarian effort -- Reichs's participation in the exhumation of a mass grave in a Mayan village in Guatemala -- is the basis for her new book, GRAVE SECRETS (Scribner, $25), and there's no doubting its terrible authenticity.
Reichs is not what you would call a natural-born writer, so the emotional responses of her heroine, Temperance Brennan, to the atrocities to which she bears witness can elicit more squeamishness than the actual bones and tissue she digs up. You can also see the wheels grinding as the plot wends its way to Guatemala City, where four women, including the daughter of the Canadian ambassador, have gone missing, and then to Montreal, where the serious lab work is done. But you can always trust Tempe to get through these rough literary patches and go back to work dissecting a shrunken head or unearthing pieces of a skeleton from the ''stew of human feces and microbial dung'' of a septic tank.