ABSTRACT
William I. Thomas was the author of works that had a lasting conceptual, theoretical and methodological influence on the later developments of symbolic interactionism, particularly through his monumental study, written in cooperation with Floran Znaniecki, concerning Polish farmers in Europe and in America. A number of factors provided Thomas with an extraordinarily wide range of experiences and cultural horizons he was able to use in an original and creative way. It is worth mentioning in this connection his early interests in literature, ancient and modern languages and natural sciences. Thomas mostly focused on matters concerning epistemology and methodology. He sought to outline the fields of study of psychology, social psychology and sociology, and indicate the research methods mostly suited to the sociological discipline. The reception of Thomas's thought on the part of the Chicago sociological school has underlined the relevance of the concept of 'definition of a situation' for symbolic interactionism.
