When John Carroll became bishop of Baltimore in 1789, his diocese encompassed what was then the United States, from the Chesapeake to the Mississippi, from the Canadian border to the Gulf of Mexico. For almost a century and a half, the archbishop of Baltimore remained the virtual leader of his church in the new republic. In The Premier See, Thomas W. Spalding chronicles the growth, tensions, and politics of the archdiocese that helped shape the history of American Catholicism.