How Long

With new technology available, the Eagles could have updated their sound for their 2007 album Long Road Out Of Eden, but decided instead to keep it familiar, sticking to the country-rock sound that made them one of the most popular bands in rock history. "How Long," with a shared lead vocal by Don Henley and Glenn Frey, sounds especially familiar, like it could have come from the 1970s. That's because it did. The song was written by the band's longtime friend J.D. Souther in 1969; the Eagles performed it live in the early '70s, but didn't record it. Souther put it on his first solo album, John David Souther, in 1972. At the time, if one member of their cohort released a song, the Eagles wouldn't do it themselves, but with 35 years separating them from Souther's version, they had no problem adding it to Long Road Out Of Eden. Souther wrote or co-wrote some of the Eagles' biggest hits, including "Best Of My Love," "Heartache Tonight" and "New Kid In Town."

A throwback to the Eagles days when they sang about outlaws and desperados, this song is sung from the perspective of a prisoner asking his girl how long she'll wait for him to get out. According to J.D. Souther (as told to Rolling Stone), it was inspired by a soldier in the Vietnam War who went AWOL, was caught, and was sentenced to murder. "His girlfriend at home had been counting down the days until he returned," Souther said. "How long? He never did."

We have YouTube to thank for the Eagles recording this song. Glenn Frey's kids were online watching videos when they came across footage of the Eagles performing "How Long" in 1974 on a Dutch TV show called Pop Gala. They showed it to their dad and had a good laugh, then Frey's wife suggested he record it with the Eagles. He took the idea to the band and they all got on board.