The mass immigration of Eastern European Jews between 1880 and 1924—some two and a half million came to the United States—caused a thorough change in the nature of New York Jewry. Following wealthier German uptown Jews, it was now marked by poor Polish or Russian Jews living on the Lower East Side of Manhattan. The Jewish quarters functioned as the hinges between Eastern Europe and the US for many immigrants. Crime was a shade of it. Jews only constituted a small minority of American society; their Americanized criminal structures, however, became one of the most influential factors of modernization of crime from the fringes to the center of American society. Through the development of the Jewish underworld, the exclusion of and the cooperation with criminals of a different ethnic background, as well as the professionalization and the struggle for respectability, the phenomenon of Jewish blue-collar crime itself experienced an Americanization. Additionally, this process of Americanization was key not only to the rise but also to the downfall of Jewish American blue-collar crime in New York.