The invention of the doughnut, which evolved from the round, fried Dutch cakes brought to colonial America, is usually attributed to Hanson Crockett Gregory, a sea captain born in Rockport, Maine. In 1947, a plaque commemorating the captain's achievement was affixed to his birthplace. While it is generally agreed that the doughnut dates back to 1847, storytellers relate several different versions of Gregory's discovery. One tale holds that Gregory was commanding a vessel called the Frypan when six men who fell overboard drowned because their bellies were full of fried cakes. Distressed by this tragedy and determined to avert it in the future, Gregory pondered the dilemma of the too-heavy fried cake. His solution was to jab a hole in the middle of the cake (thus, appropriately, making it resemble a life preserver) to lessen its danger to hungry sailors. One of the most frequently told stories about Gregory and...