Dorothy Parker dreaded repetition and found it everywhere. In 1919, when she was just 25 and only months into her stint as Vanity Fair’s theatre critic, she already claimed enough ‘bitter experience’ to know that ‘one successful play of a certain type’ would result in a ‘vast horde’ of copycats, ‘all built on exactly the same lines’. In quantity at least, this was Broadway’s golden age, just before radio and the movies ate up its audiences.