I found this in one of my music books, that I used to play at Nordstrom, and decided to play it a Mayo Clinic. After playing it, some lady came up to me and said "I'm so thankful you played this because my father sang that when I was young, and that's what encouraged me to be a Christian". She was there to visit her father, so it was touching. This song is the most popular song from the 1965 Broadway musical Man of La Mancha and is also featured in the 1972 film of the same name starring Peter O'Toole. The complete song is first sung by Don Quixote as he stands vigil over his armor, in response to Aldonza (Dulcinea)'s question about what he means by "following the quest". It is reprised partially three more times – the last by prisoners in a dungeon as Miguel de Cervantes and his manservant mount the drawbridge-like prison staircase to face trial by the Spanish Inquisition. There is a long list of versions and renditions of it. I hope you enjoy it.