As a child, the director Christopher Alden was obsessed with the musical “Peter Pan.” “My twin brother, David, and I begged our parents to let us audition to play the roles of the twins,” Mr. Alden recalled recently. “They wouldn’t let us do it.”

Now, decades later, he gets to direct “Peter Pan.”

Well, the other one.

The show Mr. Alden is staging as part of the Bard SummerScape festival at Bard College, starting on Thursday and running through July 22, is not the Mary Martin blockbuster of his youth but an earlier adaptation of J.M. Barrie’s play with a wonderful, undeservedly obscure score by Leonard Bernstein, whose centenary is being celebrated this year. That production — which starred the unlikely combo of Jean Arthur as Peter and Boris Karloff as Captain Hook — closed in 1951 after a respectable 321 performances, but then essentially disappeared.