In this seminal contribution to the sociology of knowledge, first published in 1940, Florian Znaniecki develops a typology of the variety of specific social roles that scholars have played, and investigates the normative patterns that govern their behavior. A central tool for the investigation of these problems is the notion of "social circle", the audience to which intellectuals address themselves. Znaniecki shows that thinkers do not speak to the total society but address selected segments and markets. Specific social circles bestow recognition, provide material or psychic support, and help shape the self-image of the thinker.