THE report on the library of the American Philosophical Society for 1936 includes details of the more important additions (Philadelphia: American Philosophical Society). Among the new exchanges of publications established during the year is one with the library of Armstrong College, Newcastle-on-Tyne. At the end of the year the Library contained 80,918 volumes, 48,468 pamphlets and 5,374 maps. The Library does not attempt to develop all fields of learning, but only those in which it is already strong or has historic interest. No expansion in modern books on medicine is contemplated owing to the existence in Philadelphia of a very important medical library, but fields in which development is intended include exploration ; botany, scientific and applied ; the history of science; the inter-relation of the sciences; the co-operation of learned societies and institutions. Further contributions have been made to the promotion of the Union Catalogue of Philadelphia, and the report includes a summary list of archival materials in the possession of the Library, the most important of which is the collection of Franklin manuscripts. Much work has been carried out in preparation for the issue of a descriptive catalogue of these manuscript collections.