EN
The author discusses the genesis of main theses of the theory of three sectors in the economy. The first part of the article contains general presentation of this theory developed in the thirties by A. G. B. Fisher, C. Clark, and J. Fourastie. The author focusses his attention on problems accompanying classification of the economy according to three sectors and on causalities of structural changes in the economy. In the following parts of the article there are discussed opinions of the earlier economic authors which exerted some influence on later development of the theory of three sectors. The author underlined the significance of views of mercantilists such as W. Pstty, A. Smith, W. Surowiecki, F. Skarbek and F. List.