This series comprises the main correspondence file series of the Department of External Affairs [II] from 1948 to 1970, Foreign Affairs from 1970 to 1987 and the Foreign Affairs part of Foreign Affairs and Trade from mid-1987 to the end of 1989. 

From January 1990, A1838 and the Trade series A1313 were both replaced by a computerised annual single number system (A9737). Current files were top-numbered into the new system as each Branch was converted, a process which lasted until 1992. A1838 file numbers were included on the database as part of the title field.  

This series was a subject-classified multiple number system which allocated generous blocks of primary numbers by functional areas, corresponding originally to the divisional stucture of the Department as follows:
 
   DIVISION                             PRIMARY NUMBER
 
   Political/geographical                  1-550
   Political intelligence/information    551-650
   Defence liaison                       651-700
   Economic relations                    701-850
   United Nations (incl Cwlth)           851-951
   Financial/administrative/comms        951-1450
   Consular/protocol                    1451-1950
   Security                             1951-2000
   Aid/technical cooperation            2000-
 
As staff and functions increased, difficulties were experienced with file organisation. As early as 1951, numbers allocated to the East and South East Asia geographical areas were abandoned and a fresh start was made with a new 3000/- block of numbers. Additional numbers in the 2451-2499 group were made available to defence liaison to cover such areas as SEATO. In 1963, current United Nations files were reorganised from 850-894 into an unused 900/- block of numbers.  

It was intended that every file should be top numbered but many of the closed parts retained their old numbers and were transferred under those numbers to Australian Archives. The old numbers were, in some cases, reallocated many years later to new files with different subjects. Other areas, notably the Economic Division, 'reorganised' their files by shuffling the numbers around. Even during the 1980s, a 4000/- block of numbers was allocated so that a section could start afresh with new numbers.
 
No effective central register of files created was maintained continuously and efforts to keep general name and subject indexes (except for case files) fell apart in the 1950s. 

The registration cards hold only file titles, with no dates of creation or closure and no indication of parts. This information was kept on the movement cards, which have not survived. 

Each Branch or Section within the Department kept its own updated list of current file titles, on which were sometimes marked cancellations or top-numbers, and areas sometimes maintained unofficial name or subject indexes. 
Although files were made up and controlled centrally, each area held its own files, leading to considerable duplication of contents. 
Surviving control records are piecemeal and not very reliable as top numbering and reallocation of numbers was fairly common and not consistently recorded.
 
The subject areas covered by A1838 are wide. The Department is responsible not only for collecting information about foreign countries and international organisations but also for disseminating information about Australia abroad and for maintaining diplomatic, consular, aid and cultural relations with other countries.  

Overseas missions carry out functions for all government departments, including: 

. immigration; 
. trade; 
. legal; 
. environmental; 
. defence; 
. health; 
. finance; 
. social security; 
. aviation; and 
. information activities. 

A fair proportion of all departments' international communications is carried on the external communications network.
 
Apart from foreign relations in all areas, subject matter covered by A1838 includes: 

. All forms of international treaty; 
. Convention and agreeement; 
. Radio Australia; 
. Aborigines and Torres Strait Islanders. 
. Honours and awards; 
. Art and trade exhibitions; 
. International legal matters including Law of the Sea and
  Antarctica;
. Political asylum and refugees;
. Australia's involvement in war including participation in
  multilateral defence planning; 
. Peace-keeping forces; 
. Nuclear policy; 
. Export of strategic materials and War Crimes; 
. International Red Cross; 
. United Nations agencies; 
. Global environmental matters; 
. External territories; and 
. International conferences and congresses.