“No One” details the idea that no matter what happens in life, the person you love will always be there for you.

In an interview with Billboard, Keys said:

This is one song that just wrote itself. A lot of the songs didn’t happen like that. It was one of the last songs I wrote. I needed to say this. It’s full force, classical yet vintage, desperate yet triumphant. I want people to feel my soul.

Keys performed “No One” with John Mayer at the 2008 Grammy Awards, where it was awarded Best R&B Song and Best Female R&B Vocal Performance.

Aretha Franklin also covered this for her 2014 album, Aretha Franklin Sings the Great Diva Classics.