Nearly four hundred previously unpublished letters capture the essence of an extraordinary and in some ways unlikely friendship between one of America's preeminent jurists and a younger, reform-minded colleague who would himself one day ascend to the Supreme Court. Oliver Wendell Holmes was seventy-one when he was introduced to fiery, effervescent Felix Frankfurter, who had come to Washington at age thirty to serve President Taft. The two couldn't have had more different backgrounds: Holmes was a Civil War hero of Boston Brahmin stock, while Frankfurter was a Jewish immigrant whose reformist views would lead him to help found the American Civil Liberties Union and act as key advisor to Franklin Roosevelt and his New Deal. With an introduction that provides historical background and annotations that supply context for cases mentioned, this unique collection illuminates a strong and mutually satisfying personal and professional relationship between two men whose exchanges on the meaning of law in general and American law in particular, the editors write, "found expression in their work and influenced legal and political change in their own lifetimes and in ours as well."