Who was the author of "Man of la Mancha?"

Dale Wasserman

Explanation:

Man of La Mancha is a musical with a libretto by Dale Wasserman, music by Mitch Leigh and lyrics by Joe Darion, based on the text for television I, Don Quijote, also by Wasserman, which in turn is inspired by the novel Don Quixote de la Mancha by Miguel de Cervantes. His plot starts with Cervantes himself locked in a prison while awaiting an audience with the Spanish Inquisition. To prevent his cellmates from snatching a precious manuscript that he carries, Cervantes suggests representing a theatrical function on the figure of Don Quixote, in which he and the rest of the prisoners interpret the different characters.