Most of the files in this collection date from the 1960s to 1980s, with an overall span of 1949 to 2001. They concern matters such as technical assistance, co-operation and appraisal, map printing and production, cadastral and air survey, instruction manuals, staff lists, management committee correspondence, estimates, progress and annual reports, example sheets and authority for mapping, for most of the smaller Commonwealth nations. These loose-leaf folders mostly contain a selection of letters, memos and receipts relating to the compilation of maps and the supply of maps and mapping data to various organisations, plus, in some cases, 'Tour Notes' which are DOS internal reports written after DOS personnel have visited areas. The files do not include any survey, triangulation, height, etc. data and do not usually include copies of any maps made as a result of this work (though copies of the maps may be available in the collections of Cambridge University Library Map Department who can be contacted on maps@lib.cam.ac.uk)