 "I, Don Quixote" has almost exactly the same plot and even much of the same dialogue as "Man of La Mancha".Even the famous opening two lines of "La Mancha"'s hit song "The Impossible Dream" appeared in this teleplay.According to academic research by Cervantes scholar Howard Mancing, these lines and a few others were originally written for the now-forgotten 1908 play "Don Quixote" by Paul Kester.