The Beth papers consist of series of general correspondence, series of correspondence with specific institutions and specific categories of people, case files, loose documents and collected documents. Two parallel series of general correspondence can be distinguished. Both were kept in loose-leaf notebooks. One was probably set up for short-term correspodences (c. 700 correspondents), the other for exchanges which were expected to run over a longer period (30 correspondents). As far as the contents of the series are concerned, both show a mixture of scientific and professional letters. The short-term correspondence was originally set up strictly alphabetically. However, after 1957, following an interruption of the series caused by an 8-month stay in the United States, Beth started a new alphabet each year. The long-term series was arranged alphabetically. In addition to the two main series of correspondece, Beth kept a smaller series of correspondence with specific groups of people, such as publishers, students and promovendi. On the other hand Beth compiled files relating to certain subjects, activities and functions. Subjects include his academic education (mathematics, physics, phychology, philosophy and law); public life (curricula vitae); and professorship and teaching. An extensive group of files and documents relates to Beth's scholarly output, meaning his publications, lectures and some unpublished articles and undelivered lectures. Usually one or several manuscripts were kept by Beth, sometimes filed with a draft, correspondence or other documents. Bethe kept the documents and files relating to the different categories of publications separate. He made a distinction between books, encyclopedia contributions, scientific articles, reviews and newspaper articles. Documents relating to unpublished articles and undelivered lectures were also kept separate. The majority of other files contain mostly letters. Here Beth also applied much "correspondent-subject filing". Beth also collected the work of fellow logicians and mathematicians. Often this work was sent to him in the form of typescripts or reprints. Sometimes the work of one person, or articles relating to the same subject were bound together in a binder. Most of these documents were found loose.