February issue includes Appendix entitled Directory of United States Government periodicals and subscription publications; September issue includes List of depository libraries; June and December issues include semiannual index

This list includes all serials, printed and processed, received by the Library of the United States Department of Agriculture, on a current basis, as of July 1, 1957. Only dailies or administrative use are omitted. A serial is defined as a publication that is issued either regularly or irregularly over an unspecified period of time. For the purposes of this list, a serial was considered current if it had been received in the Library at any time since January 1954, unless it was known to have ceased.