Songfacts®:

• This heavy blues-metal song has a lyric from Ronnie James Dio, who joined Black Sabbath in 1979, replacing Ozzy Osbourne. It's a very sad and lonely song, with Dio hinting at death with lines like:
  
  I'm leaving very soon
  On the way we pass so close
  To the back side of the moon
  
  It ends on a despondent note:
  
  Maybe life's a losing game
  
  These kind of morose lyrics aren't common in heavy metal but are often heard in blues and country.
• Many Sabbath fans cite Tony Iommi's guitar solo on this track as one of his best, and Iommi agrees. He said in a Songfacts interview: "I enjoyed that guitar solo because it was a different mood and was more bluesy, which is my background, really."
  
  When composing the song, Iommi hit on the riff and Dio came up with the vocal melody. Dio played an instrument (bass) and was more musical than Ozzy, which allowed him to be a bigger part of the songwriting process with Sabbath.