The Baron and the Marquis explores the history of the maxim that articulates what is now known as the parsimony principle. That maxim: any punishment that goes beyond necessity is "tyrannical." First articulated by Baron de Montesquieu and later publicized by the Italian criminal-law theorist, the Marquis Beccaria, that maxim shaped the American and French Revolutions and set the dividing line between tyranny and liberty. Thomas Jefferson believed only absolute necessity justified punishment, and the French Declaration of the Rights of Man and of the Citizen (1789) similarly allowed only "strictly and obviously necessary" punishments. In The Baron and the Marquis, award-winning author John Bessler shows the maxim's modern-day implications for capital punishment, prolonged solitary confinement, and mass incarceration. The book argues that unnecessary punishments violate the U.S. Constitution's Eighth Amendment as "excessive" and "cruel and unusual."