Abstract: The investigation of clay minerals and argillaceous rocks started in the territory of Czechoslovakia as early as the later part of the eighteenth century and has continued up to today. During this long period many interesting results have been obtained. In about 1949 modern laboratory techniques were introduced. Most of the work in this country deals with the mineralogy, petrology, and geology of argillaceous rocks, the chemical composition and physical properties of clay materials which are useful for the purposes of the ceramic, glass, chemical, construction-engineering and mining industries, etc. This paper is subdivided into the following parts: (a) Classical research period; (b) Modern research period; (c) Kaolins (primary); (d) Other argillaceous rocks of sedimentary origin; (e) Bentonites; (f) Laterites and bauxitic rocks; (g) Clay minerals in sedimentary iron ores; (h) Clay minerals in carbonaceous rocks; (i) Clay minerals of hydrothermal origin; (j) Kinds of apparatus for DTA and gravimetric thermal analysis; (k) Imbibometric study using water and organic liquids; (l) Problems of classification and terminology.