Started as International Information Bureau by four European trade unions for non-manual workers in 1904; had its seat in Hamburg; enlarged to the International Commercial Employees' Secretariat in 1910; reestablished as Fédération Internationale des Employés et des Techniciens (FIET) in 1921 with its secretariat in Amsterdam 1921-1964, in Geneva from 1964; its first secretaries were G.J.H. Smit 1921-1934 and Willem G. Spiekman 1934-1958; issues the monthly News Letter; associated as International Trade Secretariat (ITS) to the International Confederation of Free Trade Unions (ICFTU).

The FIET 24 World Congress, from 14 to 18 March 1999, decided to merge into a new international trade union federation, the Union Network International (UNI); the other ITSs involved in this merger are Communications International, the International Graphical Federation and the Media and Entertainment International.

Collection received by the IISH from the PTTI in 1979, with an accrual in 2018 probably from FNV Bondgenoten.

Collection of mainly stencilled and printed documents, supplemented with documents received by Willem G. Spiekman in his capacity of general secretary of the FIET 1934-1958. Files relating to congresses 1934-1973 (incomplete 1934-1958), consisting of agenda, resolutions, reports, speeches, attendance lists, circulars, clippings; files on the Executive Committee 1949-1962, 1974-1975, the Wages-Policy Committee 1960-1965, the Social Policy Committee 1961-1965 and on Sectional Committees 1954-1967, consisting of proceedings, reports, resolutions, circulars; files on Trade Sections Conferences 1934-1935, 1950-1970, consisting of proceedings, reports, resolutions, clippings; documents on the Arbeitsgemeinschaft der freien Angestelltengewerkschaften Mitteleuropas 1936, the Internationale Arbeitsgemeinschaft der Angestelltenjugend 1958-1968, ITS General Conferences 1965-1969, the Comité Syndical des Employés, Techniciens et Cadres FIET in the European Community 1965-1972, the European Regional Organisation of FIET (EURO-FIET) 1972-1981, the World Federation of Trade Unions (WFTU) 1946-1948, etc.; reports 1935, 1939, 1947-1949; circulars 1932-1939, 1947-1978; press releases 1964-1983; clipping on the founding congress 1904; typescript of W. Spiekman's memoirs, with notes and annexes, 1968; letters to W. Spiekman on the occasion of his retirement 1958.

Accrual 2018: documents regarding the FIET and in particular its 24 World Congress 1994-1999; documents regarding the merger organisation Union Network International (UNI) and its 1st World Congress 2000-2002.