Despite serving for more than sixteen years on the Supreme Court of the United States and authoring more than 300 opinions, Pierce Butler is one of the lesser-known Justices in American history. When his name is mentioned by constitutional scholars, it is usually to deride him for being one of the so-called Four Horsemen of the Apocalypse, a group of Justices that invalidated efforts by politicians, especially President Franklin Delano Roosevelt, to enact New Deal reforms. Scholars have characterized his role in the development of constitutional law as minimal, and he is the subject of only one full-length book, A Supreme Court Justice is Appointed, which focuses almost exclusively on his appointment to the Supreme Court rather than his...