You may not be familiar with this group by name, but if you listen to oldies radio for about 15 minutes you’ll certainly hear their music. They played anonymously on thousands of albums by others, but became known behind the scenes as The Wrecking Crew.

Comprised of about 50 studio musicians—mostly trained in jazz and classical since childhood—The Wrecking Crew appeared on nearly everyone’s records in Los Angeles in the 60s and early 70s. (New York and Nashville both had a similar pool of musicians, while in other cities, smaller rhythm sections kept busy as well, such as The Funk Brothers in Detroit—who played on just about every Motown song—and The Swampers in Muscle Shoals, Alabama.)

If you were a producer and you wanted the best players in the business backing up your artist, these cats were your first call. Sometimes, you might have needed only a few of them (as was the case with The Byrds’ “Mr. Tambourine Man,” or almost all of Simon and Garfunkel’s songs); and sometimes you might need a small rock & roll orchestra with multiple guitarists, keyboard players, percussionists, and maybe a horn section (as with The Beach Boys, or almost all of Phil Spector’s work).

No one has listed a complete discography of songs on which they played, but to give you an idea of how prevalent they were, one of their drummers, Hal Blaine, appears on 50 #1 songs and over 150 Top 10 hits. The other members of The Wrecking Crew would have appeared on most, if not all, of those songs (plus many more).

Three of the members went on to have successful solo careers under their own names: you may have heard of guitarist Glen Campbell and keyboard players Leon Russell and Dr. John. Horn player Nino Tempo–you may remember–had a #1 with “Deep Purple” before returning to session work. Bassist Larry Knechtel later joined Bread, and drummer Jim Gordon played with Eric Clapton, Joe Cocker and Frank Zappa.

So next time you hear a track by The Mamas & The Papas, The Ronettes, Sonny & Cher, The Association, The Monkees, Nancy Sinatra, Simon and Garfunkel, The Grass Roots, or The Righteous Brothers (and too many more to list), remember you’re listening to one of the best bands almost nobody’s heard of.