The Library of the Royal Commonwealth Society, born in 1868 as the Colonial Society, known successively as the Royal Colonial Institute, the Royal Empire Society and finally, and affectionately, as the RCS, is now the largest special collection of Cambridge University Library. I have told elsewhere the dramatic story of the Library's rescue from dispersal and disaster and its transfer from the old imperial heart of London, near Trafalgar Square, to Cambridge. Visual images paid an important part in the campaign to save the Library and, of all the material in its rich and varied collections, it was perhaps the photographs that most caught the imagination of the media and benefactors. The Library's visual resources were already well-known to and well-quarried by a select band of academics and picture researchers. The Library Appeal brought them to the attention of a wider public.