The song was largely written by long-time Iron Maiden guitarist Dave Murray. The rainmaker concept was started by vocalist Bruce Dickinson, who one day said in the rehearsal studio that the intro riff made him think about raindrops.
The song has no connection with the 1995 novel written by John Grisham of the same name.
Dave Murray played the guitar solo on this song.
Suggestion credit: Ryan - Bethany, OK, for above 3