Amid the halls of Harvard Law, a professor of legend, James Bradley Thayer, shaped generations of students from 1874 to 1902. His devoted protégés included future Supreme Court justices, appellate judges, and law school deans. The legal giants of the Progressive Era—Holmes, Brandeis, and Hand, to name only a few—--came under Thayer’s tutelage in their formative years.He imparted to his pupils a novel jurisprudence, attuned to modern realities, that would become known as legal r...