In October 2001, the U.S. Geological Survey requested that the Government Printing Office instruct Federal Depository Libraries that received a CD-ROM on characteristics of large surface-water supplies in the United States to destroy their copies. Shortly thereafter, the Superintendent of Documents ordered those libraries participating in the Federal Depository Library Program to withdraw this item and immediately destroy it. Subsequently, the Federal Bureau of Investigation visited several Federal Depository Libraries to determine whether that order had been carried out. This occurred without consultation with the GPO or the Geological Survey (U.S.G.S.). This series of events, and the prospect that in the wake of the September 11, 2001, terrorist attack there may be additional requests for removal or destruction of federal materials by Federal Depository Libraries (FDLs), raises a number of questions of interest and importance to librarians. This memorandum sets forth below, in a question-and-answer format, the answers to many of those questions.