The notes in question, G, G, G, E-flat, came to Beethoven fully formed, hastily, sometime in 1804 — they first appeared messily scrawled in a manuscript under some preparatory notes for his opera Fidelio. They may have had their origin in birdsong; some anecdotes claim they were inspired by the call of the yellowhammer. With the omnivorous curiosity of a polymath, Matthew Guerrieri follows their path through cultural history, from their humble beginnings (he even dwells on the symphony’s real opening, which is of course not a note at all but an eighth-rest) through early reactions (the composer Le Sueur told Berlioz, “That sort of music should not be written”) to their eventual canonization as the great opening of the quintessential great symphony. And, of course, to their cameo as background music for Tony Manero in Saturday Night Fever.