William H. Herndon, Abraham Lincoln's law partner and biographer, made a record of "secret and privatethings" about Lincoln in two memorandum books that long ago disappeared. Now diary entries have materialized, written by a woman who saw the memorandum books in 1866, and who recorded her shocked reactions to accounts of "profligacy" and "debauchery." A distinguished Lincoln scholar describes the discovery, and considers anew the collision of privacy and history