The Disappointment, or The Force of Credulity is a ballad opera composed by Samuel Adler in two acts with a prologue and epilogue, to a text by an unknown author writing under the pseudonym "Andrew Barton". William Peterson, in 1766, claimed that the opera was written by a "son of Philadelphia College," leading to speculation that the author may have been Francis Hopkinson or Jacob Duché. In his book on American drama, Walter Meserve claims that the author was named Thomas Forrest. Regarded as one of the first American operas, it was to have been performed on April 20, 1762 in Philadelphia but was cancelled at the last moment.