Most of the time, plays are just entertainments; they can be witty and insightful, even powerful and contemporary, and still function as merely satisfying divertissements. Rarely, so rarely entire decades can pass without one, a play functions in an entirely different capacity: these are works so galvanising they seem to presage, if not actually bring about, socio-political change. Henrik Ibsen’s A Doll’s House (1879) was one; Arthur Miller’s The Crucible (1953) is undeniably another; and Tony Kushner’s Angels in America: A gay fantasia on national themes is probably the greatest of the modern era. A new book, The World Only Spins Forward (2018), edited by Isaac Butler and Dan Kois, aims to contextualise, honour, and perhaps even lionise this monumental masterpiece. It paints an overarching portrait – in a gathered testimony by the people who worked on, wrote about, and/or witnessed it – of the play’s cultural roots and its progression into the American theatrical canon.