Celebration—acting variously as a binding force for a community or as a self-congratulatory act, carried out in settings as intimate as a family dinner and as grand as tickertape parades—would seem to be so fundamental to human behavior as to operate ahistorically. But the various ways we celebrate—how we crown our heroes, how and when we clap during an opera, how we wave our flags at victory celebrations, how we fête our celebrities—are structured in vastly different fashions depending on context and period. 52, with a special section on "Celebration," features D. Graham Burnett on the history of confetti; George Pendle on stamps celebrating other nations’ technological achievements; and James Trainor on the martial motifs of Israeli greeting cards. Elsewhere in the issue: Andrea Scott on the color bittersweet; Martin Kemp on Leonardo’s library; and Sasha Archibald on the history of book indexes.