Consider the warhorses: those pieces of music that have seemingly permanently wedged their way into the standard kit of Western cultural literacy, repeated and reprogrammed as if by reflex. And consider probably the most well-known of warhorses, Beethoven’s Fifth Symphony.

I have spent a good part of the last several years working on a book about Beethoven’s Fifth. It is a little strange to spend so much time in the company of a 200-year-old piece of music. For one thing, our relationship to music has profoundly changed since the symphony’s premiere. Music, today, is a commodity: I can listen to Beethoven’s Fifth whenever I want. In fact, I can’t even remember the first time I heard Beethoven’s Fifth. It’s always been there. Its familiarity is almost oppressive, so much so that ignorance of it seems almost willfully eccentric. (Such, perhaps, was the case of André Breton. In 1930, having finished his film “L’Âge d’or” — or “The Golden Age” — Luis Buñuel arranged a private screening for a group of his fellow Surrealists. Hearing Beethoven’s Fifth on the soundtrack, Breton, the founder of Surrealism, leaned over and whispered to a friend, “Who wrote that? It’s very beautiful.”)