A silly idea, perhaps, but there was also some truth in "The Life Millennium," a book that rated the top personalities and events of the past 1,000 years. Among the people, Martin Luther ranked third behind Edison and Columbus, beating Galileo, da Vinci and Newton. The Reformer's remarkable career is treated in the feature film "Luther" and now in two new biographies, each scholarly, yet written for swift, enjoyable reading: •"Martin Luther: A Life" (Augsburg) by James Nestingen of Luther Seminary, St. Paul, Minn. •And "Martin Luther" (Viking) by Martin Marty, professor emeritus at the University of Chicago. Alas for...