Songfacts®:

• Letter To You has a theme running through it of mortality and aging. The losses of E Street Band members Danny Federici and Clarence Clemons in 2008 and 2011, and the 2018 death of George Thiess - founding member of Springsteen's first band, The Castiles - had a large influence on the project. The Boss starts the record with this preface about mortality and death that lets the listener know what the album is going to encompass.
• The song starts solemnly as Springsteen evokes the traditional blues, country and folk metaphor for death.
  
  Big black train comin' down the track
  Blow your whistle long and long
  
  A loved one has passed away without warning, and Springsteen is feeling their absence.
  
  One minute you're here
  Next minute you're gone
  
  In spite of his sadness, Springsteen can still celebrate their lives together.
  
  Autumn carnival on the edge of town
  We walk down the midway arm-in-arm
  
  Autumn is figuratively a season of maturity or decay, which precedes winter or death. "The edge of town" goes back to Springsteen's 1978 album, Darkness on the Edge of Town, and its title track.
• Springsteen explained to Apple Music the song "just sort of a little tip of the hat to where the record was going to go and a little slightly connected to [his previous album] Western Stars. It was a little transitional piece of music."
• Letter To You is bookended by two songs about mortality and death. It begins with this song and closes with "I'll See You In My Dreams."
• Bruce Springsteen recorded his previous album, Western Stars, without the E Street Band. By starting the song alone before being slowly joined by the other musicians, Springsteen is providing a bridge and then departure from his recent solo work. "You start with that opening song and the line, one minute you are here and the next minute you are gone and then put that in the perspective of someone who is 70 years old and writing a record about their life," pianist Roy Bittan told Uncut magazine. "It's a strange song to start what is supposed to be a rock record, but then you realize that is the introduction to what the rest of the record is about."