During the House Judiciary Committee’s impeachment hearings last week, I was surprised to hear several constitutional law scholars cite Dr. Johnson’s Dictionary for definitions of treason, misdemeanors, bribery, etc. They were referring to Samuel Johnson’s 1755 Dictionary of the English language. It is not altogether uncommon to hear the name Dr. Johnson—usually in reference to some bon mot he delivered in the course of his life—but it is rare to hear anyone invoke his famous dictionary, the first great dictionary of English.