Abstract: Attempts to find a generally acceptable scheme of classification and nomenclature for clay minerals by the nomenclature committees of The Clay Minerals Society (C.M.S.), the Comité International pour l'Étude des Argiles (C.I.P.E.A.), and the International Mineralogical Association (I.M.A.) are summarized. The C.M.S. committee has been working on this problem continuously since 1961 and has transmitted its views to C.I.P.E.A., first at the time of the Stockholm meeting, 1963, and subsequently, in more detail, after receiving the first draft of the C.I.P.E.A. proposals. The C.I.P.E.A. committee held discussions in Stockholm, 1963, and subsequently submitted a first draft to 32 nations; from the replies received, a final draft of the C.I.P.E.A. proposals was prepared and submitted to the I.M.A. in 1964. The report from the I.M.A. was made available in August, 1965.