These files record the general administrative activities of the Department of Defence. The series was raised in 1924 when Army Headquarters set up its own registry. (Formerly Army administrative matters were recorded on the one central Defence series, CRS A1952. CA 2671, Army Headquarters, continued CRS A1952 together with its control records while Defence Central Registry began this new series, with new control records).

The Defence series is distinguished from the contemporary Army series by the secondary numbers starting at '401'. The matters it records extend from supplies, and accounts to ceremonial questions and superannuation. The series excludes security classified matters which are recorded in a separate classified series (CRS B197) and matters specifically relating to arbitration which were recorded in a portion of CRS A1952 continued by Defence, Central Registry (classes 665/2/- and 665/3/-). It deals only with administration of the co-ordinating and policy making functions of Defence, not matters relating to the forces, all of which had their own administrative correspondence series by 1924.

This series is a subject classified (multiple number)folio-registration system. The subjects it covers were listed alphabetically and then numbered, the number range being 400-648. These numbers are the first element in the registration number.

These subjects are further subdivided and numbered, in this series beginning with 401. This forms the secondary element of theregistration numbers for the series and is its identifying characteristic - '401' class. The third element of the registration number is a chronologically assigned, running number for items registered within each class. The subject classification system aims to make the correspondence arrangement self-indexing.

At the time when this series began files as such were unknown. Each paper received was stamped registered separately in its appropriate subject class in registration booklets (CRS A1942). When a second paper was received it was registered with a new number and the first paper was brought forward and placed with the second. In this way bundles of papers on approximately the same subject could accumulate. These do not have file covers or titles and the papers all have different registration numbers. Usually the bundles consist only of correspondence received and internal papers. Correspondence out was recorded in letter books, the reference being given in theregistration booklets.

In August 1934 Defence Central Registry raised a new series (CRS A1567) which dealt with matters relating to civilian personnel. These matters had previously been recorded in Defence's portion of A1952 (classes 665/2 and /3) under the subject 'arbitration' and in this series. There is a certain amount of top-numbering of A664 papers into the new series. Also at some time during the life of the series it was realized that the class 556/406/-, 'Pay, Civilians at Naval Establishments, Misc', duplicated a class maintained by Navy (see class 556/201/- in CRS B4881). The files and control records relating to this class were consequently removed from this series andtransferred to Navy for reference. They are now found in CRS B4881.

In 1939 the Defence Department was re-organised and the three services were separated into three new Departments. This is reflected in the records by the closing of this series in January 1940 and raising of a new series (CRS A663) distinguished by the 'O' prefix.

There are files held in Melbourne as MP729/6 that are apparently related to these files but the scope of this relationship is hard to establish due to the poor quality of the registration for MP729/6. If the records are the same then the majority of the series is held in VICSO.