Louis Bamberger (1855–1944) was the epitome of the merchant prince as public benefactor. Born in Baltimore, this son of German immigrants built his business—the great, glamorous L. Bamberger & Co. department store in Newark, N.J.—into the sixth-largest department store in the country. A multimillionaire by middle age, he joined the elite circle of German Jews who owned Macy’s, Bloomingdale’s, and Filene’s. Despite his vast wealth and local prominence, Bamberger was a reclusive figure who shunned the limelight, left no business records, and kept no diaries. He remained a bachelor and kept his private life and the rationale for his business decisions to himself. Yet his achievements are manifold. He was a merchandising genius whose innovations, including newspaper and radio ads and brilliant use of window and in-store displays, established the culture of consumption in twentieth-century America. His generous giving, both within the Jewish community and beyond it, created institutions that still stand today: the Newark YM-YWHA, Beth Israel Hospital, and the Newark Museum. Toward the end of his career, he financed and directed the creation of the Institute for Advanced Study at Princeton, which led to a friendship with Albert Einstein. Despite his significance as business innovator and philanthropist, historians of the great department stores have paid scant attention to Bamberger. This full-length biography will interest historians as well as general readers of Jewish history nationally, New Jerseyans fascinated by local history, and the Newarkers for whom Bamberger’s was a beloved local institution.