"The"apartment community" of the 1960-1974 apartment boom is used to examine Gropius' 1929 hypothesis that in the period from 1920 to the Year 2000, the apartment and later a communal dwelling will overtake and succeed the single family house as the predominant residential form in Ame rican industrial cities and urban areas, associated with evolutionary social changes. Census and economic data are used to describe two twentieth century apartment booms and to analyze their relation to sociological and related changes. An attempt is made in the light of these, to re formulate Gropius' hypothesis for systematic testing and for assessing urban housing policy."