This is the first part of a textbook for students of sociology, and for those students of other social sciences who wish to make use in their work of the research methods elaborated in the course of the develop­ ment of empirical sociology over the last few decades. The development of empirical sociological research in our country and the growing demand both for a practical application of its results and for graduates of sociological studies in various fields of social practice testifies to a much broader trend. It is evidence of a desire to base our understanding and conscious transformation of social phenom­ ena on a sound, scientific perception of social processes and the mechanisms governing them. The increasing volume of studies in Poland is accompanied by a growing need for a particular type of re­ search method, namely one in which questions addressed to the socio­ logist would be answered in a manner as free as possible of conclusions based on impressions and defining as unambiguously as possible both the limits of the generality and the degree of validity of the inferences drawn from the results of the research. These conditions are met by the so-called standardized methods of investigating social phenomena which, together with statistical methods of analyzing collected material, consti­ tute the principal means of conducting sociological research in the world today.