Found
this:
Slash: The song "Ain't Life Grand," [is special to me]. There's a story behind this. "Ain't Life Grand" is a song that I penned for Les Paul. I did it with Iggy Pop, Lenny Kravitz, Kenny Aronoff and Duff McKagan. We recorded this song and it was supposed to be on a Les Paul tribute record. Time went by and all of a sudden I went 'What ever happened with that tune?' It was called "Burn Out" back then. Les was really sick and I thought Warner Bros is just waiting for him to croak so they can really capitalize on this record, so I bought the song back. I had the music and the exact same arrangement that we do, so me and Rod sat down one night in the studio and we created this song, "Ain't Life Grand" to the already more-or-less existing music. Then the horns came into it and [created] the whole vision of what the song was supposed to sound like. That, to me, seems really special because it was a conglomeration of the entire band doing this thing.