When it premiered, no one would have thunk it. In 1975, the new Kander and Ebb musical Chicago opened two weeks after the premiere, on May 21, 1975, of A Chorus Line. The latter was a monster hit that captured the Pulitzer Prize for Drama. It ran and ran. Meanwhile, Chicago closed after 936 performances. And yet, having been revived in 1996, Chicago is now Broadway’s longest-running musical. The two shows share a similar structure of soliloquies and star turns. But where A Chorus Line is earnest, elegiac, and warm, Chicago is cynical, forward-driving, and cold—a brilliant vaudeville. Sentimentality dates you, in life as well as in art, so perhaps it’s no surprise that Chicago came out ahead. It’s looking back now, however, if only for one night. As the show celebrates its 25th year on Broadway, a special performance welcomes previous cast members to the stage. Who they are is a surprise. —L.J.