A basic description of all the collections held in the Warburg Institute Archive with a summary of both content and extent is available online in the catalogue of the University of London's archival holdings (to see all Warburg Institute Archive material, choose Advanced Search and under Repository select Warburg Institute).
The correspondence collection contains Aby Warburg’s personal and institutional correspondence (WIA GC), and the correspondence between Aby Warburg and his family (WIA FC) from 1873 to 1929, followed by the correspondence of the Kulturwissenschaftliche Bibliothek Warburg (WIA GC), currently catalogued up to 1933. The correspondence collection is catalogued at item level. For Warburg’s lifetime (up to 1929) each entry contains an abstract of the content of the item.
The collection of 104 index card boxes (WIA III.2.1.ZK) is catalogued at file level.