What do appellate judges cite? Lawyers have hunches, but this study, which tallies more than 13,000 citations from three different appellate courts (including the U.S. Supreme Court), transforms those hunches into concrete data—with some twists and curiosities along the way. Unlike previous studies that focused on just one type of authority, this study considers it all. The results reveal courts’ citation preferences for binding precedent (including the age of cited cases), persuasive precedent, codified law, secondary sources (including a topical breakdown of law-review articles), and nontraditional sources such as books and websites. Some of the statistics challenge assumptions. Readers will see, for example, textualist jurists ignoring dictionaries and citing legislative history. And the results are sprinkled with oddities, from an operatic libretto to a 16th-century Elizabethan statute. The Article concludes with a statistical snapshot of the typical U.S. Supreme Court opinion (majority and dissent) and the typical state court-of-appeals opinion.