Christmas will be upon us with depressing speed, and it may comfort you through the long night watches to reflect that jolly old St. Nick was at one time also the patron saint of thieves. Not to mention pawnbrokers, students, husbandless girls, and anyone else who cared to claim the protection of an exceedingly popular saint. Ebon tidily summarizes what is known of the original St. Nicholas--a shadowy 4th-century figure said to have survived the persecutions of Diocletian, fought against the cult of Artemis at Ephesus, become Bishop of Myra (now Demre in Turkey), and defended the true faith at the Nicene Council by socking the heretic Arius (here unaccountably called ""Arian""). If such a person as Nicholas really existed, he seems to have been distinguished for a crusading piety which has little to do with fat, merry Kris Kringle. Ebon traces the modern Santa Claus myth to the 19th-century New York vogue of sentimental fancy about the colonial days of Nieuw Amsterdam. Synthetic though Santa may be, Ebon finds him a not unworthy descendant of the doughty Greek bishop, a conclusion you may find hard to swallow despite various ritual gurglings about child-like joy and giving of ourselves. But it may sound better to loved ones unwrapping this well-timed offering under the tree on Christmas morning. Cliche-filled but informative and pleasant.