Sorokin, Pitirim A. creator New York Free Press 1959 645 p. The Fluctuation of Social Stratification (Page-23), Social Mobility, its forms and Fluctuation (Page-133), Population of Different Social Strata (Page-215), Fundamental Causes of Stratification and Vertical Mobility (Page-337), Present Day Mobile Society (Page-381), The Results of Social Mobility (Page-493). Pitirim A. Sorokin Sociology 301.44,SOR 20230228120546.0