Higglety Pigglety Pop! is the second of Knussen's two extraordinary fantasy operas created in collaboration with the acclaimed author Maurice Sendak. It was composed between 1984--5 but finding its final form after a number of substantial revisions in 1999. The opera, subtitled "There Must be More to Life," is the story of a well-fed Sealyham terrier, Jennie, who escapes boredom to become prima donna of the Mother Goose World Theatre. Brimming with invention, this hour-long work culminates in a witty opera-within-an-opera, complete with a lopsided---and slightly screwy---overture, absurdly abrupt changes of tone and gear, and numerous madcap false endings.