Records relating to various peace movements. They include correspondence and papers, 1920-34, relating to the establishment of the League of Nations Union (Wales) and its development up to 1934; various memoranda and policy documents, minutes of various committees and sub-committees, papers concerning the organisation of conferences and meetings, monthly reports, and lists of local branches, their officials and their activities; correspondence, printed material (including some press cuttings), 1935-44, relating to the work and activities of the League of Nations Union (Wales), especially its council; correspondence and papers, 1917-49, concerning the New Europe Society, League of Free Nations, and the League of Nations Union; various papers, 1937-54, relating to the League of Nations Union and similar bodies and organisations, including the agenda and minutes of its Welsh National Council, and various committees and sub-committees, memoranda and reports, circulars and circular correspondence, and newsletters; documents, 1922-39, concerning the background to the establishment of the New Commonwealth, its administrative records, 1932-56, related papers and memoranda, 1929-56, extensive files of correspondence concerning its administration, activities, especially its expansion abroad, 1932-54; documents relating to early atomic energy initiatives, 1945-48; correspondence and papers, 1942-51, relating to the various campaigns to secure federalist solutions and a system of world government, New Commonwealth publications.

A wide range of leaflets, pamphlets etc., 1917-57, many of these concerning the activities of peace movements and peace initiatives. including some of the publications of the New Commonwealth Society. Some of the material reflects various aspects of Welsh life.