There was a time, a biblical 40 years ago, when Tevye the milkman, seen through the eyes of a Broadway audience in "Fiddler on the Roof," was representative of the Jewish everyman. An impoverished shtetl dweller, filled with fantasies of becoming rich, he was ultimately helpless against the combined forces of persecution and encroaching assimilation. After all those sunrises and sunsets, Tevye's traditions eventually toppled under the weight of modernity and the social upheavals of the new world. Today, however, when most people think of Jews, Tevye would not immediately come to mind. Indeed, the world of the European shtetl, with its deprivations and insularity, isn't recognizably Jewish at all. For many people, Jews are now mainstream, and their culture is as ubiquitously American as a bagel.