More, for certain, than most readers will want to know about ""survival cannibalism""--chiefly in the context of 19th-century shipwrecks--but extensively researched and entertainingly delivered. Kent U. law professor (and, clearly, nautical buff) Simpson uses the 1884 case of the British yacht Mignonette as the centerpiece for this study of the problems of reconciling the instruct for survival with a moral code that respects the sanctity of human life. Bound for Australia with a crew of four, the Mignonette foundered in the South Atlantic; the crew took to the small dinghy, in which they drifted over a thousand miles in 24 days before being picked up. By then, however, they were three: the youngest crew member had weakened badly and, said first mate Edwin Stephens, ""the Master [Tom Dudley] hastened his end by bleeding him."" After which, they ate the body (""we was all like mad wolfs,"" Dudley explained later). In an exhaustive survey of shipwreck accounts, Simpson demonstrates that this practice was not uncommon: ""what sailors did when they ran out of food was to draw lots and eat someone."" Officialdom often turned a blind eye to the custom (and jurisdiction to prosecute was often murky, anyway); but Dudley and Stephens were brought to trial (the third survivor was not charged), to their own clear surprise and amid considerable public sympathy. The Home Office, however, seemed determined to create a leading case and rebut the argument that a doctrine of necessity could, under proper circumstances, justify homicide. In the end, after a complex procedural tangle (Simpson guides readers through the maze nimbly), the two men were convicted of murder; pro forma death sentences were rapidly commuted to six months' imprisonment. Simpson sets the Mignonette's story against a wealth of background on survival cannibalism generally, shipwrecks, the development of government regulation of shipping, the wretched conditions under which 19th-century sailors worked, and a sampling of contemporaneous ballads. (""He stabbed and killed him with a small pocket knife,/They drank human blood to preserve their own life."") Worthy of a larger audience than the offbeat topic is likely to command.