Experts have authenticated 233 surviving copies and the Folger, named after a Standard Oil exec who collected Shakespeare memorabilia and located in Washington D.C., has 82 of them, more than anywhere else (the British Library only has five).
A whole section of the exhibit is devoted to the Adler family. The patriarch Jacob was celebrated for his Yiddish versions of Shakespeare and his daughter Stella later became an influential member of the Group Theater and the founder of the Stella Adler Studio of Acting, where she mentored, among others, Marlon Brando and Robert De Niro.
It's also fun to see the costumes Zero Mostel wore as Tevye the Milkman in Fiddler and Barbra Streisand wore as the great second Avenue vaudevillian Fanny Brice in Funny Girl.
A major highlight were the sketches and models by the Russian-born set designer Boris Aronson, who began his American career on the Lower East Side before moving uptown to Broadway where he eventually won six Tony awards for his stylized sets for the original production of Cabaret, Follies and Company.