Issues of demography and identification among Jews in the United States stand at the crossroads of at least two different complementary research perspectives. The first, directly focuses on the observed trends among American Jews and is concerned with description and interpretation of these trends and their possible implications for the longer term continuity and viability of the American Jewish community. The second, more theoretical perspective, considers Jews in the United States as a casestudy which may contribute in a broader effort to conceptualization of the definition, meaning and significance of religious and other types of socio-cultural groups in contemporary societies. The materials presented in this paper relate directly to the first of these two approaches. The data presented are our own new, and so far, unpublished processings of the 1990 National Jewish Population Survey, sponsored by the Council of Jewish Federations in New York, and directed by Profs. Sidney Goldstein of Brown University and Barry A. Kosmin of The Graduate School and University Center, CUNY and the North American Jewish Data Bank (NAJDB), with the support of a National Technical Advisory Committee. It is hoped, though, that the paper will stimulate discussion of a broader scope about the sociology of contemporary Judaism, particularly in North America, and about the socio-demographic development of religious groups more generally.