Researchers in psychoanalysis and related fields can make use of a wide range of primary sources, both printed or online, in their research. Some examples of this type of resource include:
The Library has a number of interesting special collections in Psychoanalysis and related fields, some of which are of considerable importance. A handful are book collections (e.g. Holt), others are archival (e.g. Balint), and the remainder are a mixture of materials (e.g. Freud).
The Institute of Psychoanalysis has some useful links to UK archival collections, including the Wellcome Institute Library, which is an important repository, including the Melanie Klein papers and collections of other analysts
In the US, the Library of Congress has digitised the Sigmund Freud Collection of over 20 000 items including the personal papers of Freud
Whilst printed collections & archives remain important, recent years have seen a massive increase in the number of digitised primary sources. Some of these are freely available from sources like national archives, national libraries & research universities, and others can be purchased through commercial vendors who specialise in this area. It might be worth exploring some of the subject guides, in particular History and Sociology, which list many interesting resources.
A few examples include: