"Box of Rain" is a song by the Grateful Dead, from their 1970 album American Beauty. The song was composed by bassist Phil Lesh and lyricist Robert Hunter, and sung by Lesh. In later years, the song was a favorite and the crowd would shout "Let Phil sing!" to hear the song.

"Box of Rain" is a song that is drawn from American folk and country musical roots. This is true of many Grateful Dead tunes, and most of the songs on American Beauty and their other 1970 release Workingman's Dead. As the first song on American Beauty, it was also the first Grateful Dead song released on record to feature Phil Lesh as the lead vocalist.

The song also featured two musicians who are not in the band. Dave Torbert played bass, while Lesh played acoustic guitar. David Nelson (of New Riders of the Purple Sage) plays the lead guitar with a Fender Telecaster, while Jerry Garcia plays the piano. While many describe Dave Nelson's Telecaster solo as being performed on a b-bender equipped guitar, the solo was recorded before he owned one, and was performed using traditional bending technique.

According to lyricist Hunter, Lesh "wanted a song to sing to his dying father and had composed a piece complete with every vocal nuance but the words. If ever a lyric 'wrote itself,' this did—as fast as the pen would pull." Lesh practiced the song driving to the nursing home where his father lay with terminal cancer.

According to an interview of Hunter by Steve Silverman, as asked by Silverman, "The song "Box of Rain" began as a rough vocal outline from Phil Lesh. How does that process work?". Hunter replied, "Scat singing: Dum-dum dum, da-da-da-da, bump-dum-dum-dum-dum, dee-dee-dee. I'm able to translate peoples' scat. I hear English in it, almost as though I write down what I hear underneath that. I hear the intention. It's a talent like the Rubik's Cube, or something like that, and it comes easily to me. Which might be why I like Language poetry. I can tell from the rhythms, or lack of rhythms, from the disjunctures and the end stoppages, what they're avoiding saying-- the meaning that they would like to not be stating there, comes rushing through to me. I understand dogs. I can talk to babies."

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