From 1789 to 1985 the federal government has created some 170 million cubic feet of records. At the end of 1984 it had accumulated over 40 million cubic feet of records, including 1.4 million cubic feet of permanent archives in the custody of the National Archives. Thus, 130 million cubic feet of federal records have been destroyed. Most of the destruction, about 120 million cubic feet, took place subsequent to the creation of the National Archives and Records Service (NARS) in 1949 and to the passage of the Federal Records Act of 1950. The success the federal government has experienced in the disposal of records with insufficient values to warrant retention during the past thirty-five years is, in part, the result of the records disposition groundwork that was laid before 1950. This groundwork, consisting of congressional legislation, archival theory, National Archives efforts, and agency practices, is little understood or appreciated by today's archivists. Yet, archivists should understand and appreciate past disposition policies and practices, because much of what is done today in records disposifion is based upon the pre-1950 policies and practices.