1) Starting position for the archival preservation of files at the AOK regional offices in Westphalia-Lippe: In the course of a comprehensive change in the organisational and self-administration structures of the Allgemeine Ortskrankenkassen in the mid-1990s, it became clear in the archival expert discussion that the AOK sources represent an important and comprehensive reflection of economic and socio-historical structures at regional level. The regional relevance of the tradition is derived from the historical development of the general local health insurance funds: At the end of the 19th century, the funds were established at the local level of the municipalities and in the course of time adapted to the administrative structure of the districts or cities by merging funds. In this respect, the formation of traditions by municipal archives within the framework of their responsibility for the documentation of local/regional living environments is an obvious conclusion. This approach has been taken up by the LWL Archive Office for Westphalia, which played a mediating role between the Westphalian municipal archives and the AOK Westphalia-Lippe in the implementation of the archival preservation of the historical records located in the AOK regional directorates. As a result, negotiations were conducted between the Central Directorate of the AOK Westfalen-Lippe in Dortmund for the AOK Regional Directorates subordinated to the Central Directorate and the LWL Archive Office for Westphalia in Münster for the participating municipal archives on the archiving of regional AOK sources. 2. cooperation between the AOK Westfalen-Lippe, the LWL-Archivamt and the Kommunalarchiven for the archiving of AOK-files: After the first talks on the archiving of AOK files had taken place in 2002, it finally took until April 2008 before a cooperation agreement could be concluded between the LWL Archive Office for Westphalia and the AOK Westfalen-Lippe on the "Archival indexing of the core records located in the regional offices of the AOK Westfalen-Lippe up to the key year 1994". This agreement regulates in principle the safeguarding of the historical core tradition of the Allgemeine Ortskrankenkassen in Westfalen-Lippe and their predecessor institutions, which were independent up to the cut-off year 1994. It includes the evaluation, transfer and indexing of the relevant source material by the LWL-Archivamt für Westfalen and the subsequent decentralized storage and utilization in the regionally responsible municipal archives after the archiving processes. The allocation of the individual AOK holdings to the municipal archives is based on the organisational structure of the Allgemeine Ortskrankenkassen before the fundamental restructuring through the merger into the AOK Westfalen-Lippe in 1994. 27 municipal archives function as target archives for the 27 independent Allgemeine Ortskrankenkassen in Westfalen-Lippe which existed until the beginning of 1994. 3. taking over and indexing the archival core records of the AOK Dortmund and its predecessors: The separation of the archival documents of the AOK Dortmund and its predecessor institutions took place at the Regional Directorate Bochum/Dortmund/Herne in the Dortmund office on 17 and 18 April as well as on 5 October and 23 November 2009. The transmission of the minutes of the AOK Dortmund makes a relatively closed impression overall. Of the predecessor institutions, only the records of the AOK Hörde from 1909 - 1920 and the records of the Special Local Health Insurance Fund for the Restaurant and Pub Industry from 1893 - 1933 are documented. In the area of social elections, with the exception of the 1974 elections, documents on all elections are available. The articles of association have been handed down since 1899. The documentation of the financial administration of the Fund began in 1903. A special feature of the AOK Dortmund was a closed file layer from the 1st half of the 20th century to the end of the 1950s. These files were evaluated on site together with the responsible archivists of the Stadtarchiv Dortmund and added to the core collection. In terms of content, the files deal with the Fund's contribution and benefit system, relationships with other insurance providers and the numerous AOK Dortmund's own operations. Furthermore there are protocols of the BKK of the Schüchtermann in the stock.