Source: Paul Bence, Flickr. Licence.
All books, dissertations and other physical resources in the SIA London should be found by Summon, but there may be occasional errors. In addition, new items may take a few days to appear in Summon. It's possible to search for physical resources in the book catalogue, which is complete and up-to-date. However Summon often has more information about the contents of our books, so it is the best starting point.
For dissertations from other colleges and universities, Summon will find many, because it includes ProQuest Dissertations and Theses Global: Humanties and Social Sciences. However there are many other options to try, listed in the other dissertations and theses guide. In particular, the British Library and Global ETD are good places to start.