I've been droolin...

This was Led Zeppelin's first US single, and their only US Top-10 hit. Some of their most popular songs, like "Stairway To Heaven," were not released as singles.
Atlantic Records pressed copies of the single to release in England, but Peter Grant, their manager, wouldn't let them. He felt releasing singles in England would hurt album sales, and the band thought that one song was not a good representation of any group. In the US, it was acceptable because more people bought singles.
Blues great Willie Dixon sued the band, claiming they stole this from his song "You Need Love." The band reached an agreement with Dixon, who used the settlement money to set up a program providing instruments for schools.
Led Zeppelin used this as the basis for a medley they performed in their later shows. They had lots of songs by then, so they used the medley to play snippets of their popular songs they did not want to play all the way through. They incorporated various Blues songs in these medleys as well, notably "Boogie Chillen" by John Lee Hooker, which was often followed by what they called "Boogie Woogie, by Unknown," and "Let's Have A Party" by Wanda Jackson. They would put this in when Robert Plant would yell, "Way Down INSIDE." (..more>>)