In 1947 a sub-committee of the Library Committee was appointed to take charge of the arrangements for the celebration of the tercentenary of the Society’s foundation. The sub-committee proceeded to consider the ways in which the tercentenary could most fittingly be celebrated, and in the course of their deliberations had brought to their attention the question of the arrangement and cataloguing of the Society’s archives and manuscripts. Upon investigation, it was found that the collections were in a state of considerable disorder, and that the task of arranging and cataloguing them would occupy the undivided attention of an assistant for a period of some years. Unfortunately, the expenditure necessary to carry out such a project was more than the Society could at that time support, and it appeared for a while that the scheme would fail for lack of funds. In November 1949, however, the Pilgrim Trust generously made a grant to the Society sufficient to cover the expenses of the scheme for a period of three years, and, an assistant having been appointed, work began in January 1950. By February 1952 the progress which had been made was so encouraging that the Pilgrim Trust agreed to make a further contribution, to enable the Society to continue the work so promisingly begun. While it would be too much to say that the cataloguing is now complete, it is certainly true that the collections are now better arranged and more accessible than they have, in all probability, ever been before; and it was therefore decided that Mr Bluhm, the assistant who has been employed on the scheme since its inception, should draw up a general guide to the archives and other manuscripts, in which the contents of the collections should be summarized, and the work done by himself related to that done by previous cataloguers. I am sure that Fellows will be glad of this opportunity of reading Mr Bluhm’s report in Notes and Records and to see the progress that has been made thanks to the generosity of the Pilgrim Trust. Now that our archives and manuscripts have been put in order and catalogued, owners of documents relating to the Society or its Fellows may be encouraged to deposit them in the Library for reference and safe keeping. I. Introductory remarks 1. The purpose of this Guide is to provide a general summary of the Society’s archives and the other MSS in its possession, to show in what manner they are catalogued, and what form the catalogues take. As far as the writer is aware, this is the first time that any such Guide has been prepared ; excellent catalogues have been made of the various series of guardbooks which contain the greater part of the archives of the 17th and 18th centuries, but:— (a) no attempt has hitherto been made to give any account of the 19th century archives, and these are in a much more complicated state than those from earlier centuries; (b) the attention of previous cataloguers has been directed for the most part to the official correspondence and papers of the Society. However, much other interesting manuscript material has been acquired from time to time, and it is desirable that some account of this should also be given.