Reddit reviews The Tyrannicide Brief: The Story of the Man Who Sent Charles I to the Scaffold

This actually goes to a fundamental debate on the nature of sovereignty and of law: Prior to the Magna Carta, the legal concept was 'Rex is Lex' - that is, the King was the Law - Law did not exist except through the person of the King. Therefore it was literally impossible for the King to do anything illegal, because the King was the fountainhead of law on earth. The Magna Carta was the first concept that implied that there was some law higher than the sovereign - that the King's power was not whatever he said it was, but was bounded in some ways by the requirements of 'Kingly Behavior'. For a good, ground's eye view of an unsung legal hero who embraced and extended this legal concept, see The Tyrannicide Brief: The Story of the Man Who Sent Charles I to the Scaffold. Highly recommended.