First established 150 years ago, Chicago Sinai is one of America's oldest Reform Jewish congregations. Its founders were upwardly mobile and civically committed men and women, founders and partners of banks and landmark businesses like Hart Schaffner & Marx, Sears & Roebuck, and the giant meatpacking firm Morris & Co. As explicitly modern Jews, Sinai's members supported and led civic institutions and participated actively in Chicago politics. Perhaps most radically, their Sunday services, introduced in 1874 and still celebrated today, became a hallmark of the congregation. In Sundays at Sinai, Tobias Brinkmann brings modern Jewish history, immigration, urban history, and religious history together to trace the roots of radical Reform Judaism from across the Atlantic to this rapidly growing American metropolis.  Brinkmann shines a light on the development of an urban reform congregation, illuminating Chicago Sinai's practices and history, and its contribution to Christian-Jewish dialogue in the United States. Chronicling Chicago Sinai's radical beginnings in antebellum Chicago to the present, Sundays at Sinai is the extraordinary story of a leading Jewish Reform congregation in one of America's great cities.