The Museum preserves a larger number of personal items used by Tesla during his life. These items are today divided among several of the Museum’s collections. The Museum’s greatest treasure, however, is Tesla’s personal archive whose documents, manuscripts, scientific notes, calculations, diagrams, drawings and letters make up a total of 163,911 call numbers. This material, created over a long time (1856-1943), includes documents which are extremely diverse, both in content and in form.
Among them are handwritten pencil notes, printed business cards with and without annotations, cancelled postage stamps, accounts on the cheapest paper, checks and printed forms with handwritten contents, and typewritten texts with duplicates, as well as diplomas written in colored ink on parchment, a charter with an intaglio stamp, india ink drawings on tracing paper, blueprint copies of plans and many other items.
Given the age and variety of this material, it may be said that most of it is relatively well preserved. The entire archive is kept in 548 boxes (which are the basic units for processing and storage of the material) and catalogued in seven units according to the subject matter of the documents.