MARGARET WARNER: In the last several years, authors Stephen Ambrose and Doris Kearns Goodwin have garnered much attention, including here on the NewsHour, for their best- selling histories. But in the last two weeks they have attracted a different kind of notice: Charges of plagiarism and improper citations for passages of their books apparently taken from other writers. Ambrose has authored thirty books, eight in the last five years, on everything from world wars to American Presidents.