"[...] it's a band whose line-up changes quite a lot, which is a good thing in this case, as each newcomer brings a certain amount of freshness to each album. As Adrian Smith was as new as I was when I produced Killers, I can't compare with the guitar player he was replacing. But it's certain that Bruce Dickinson has improved the band as compared with Paul Di'Anno, who was isolated at the human level and who wasn't very productive. As for Piece Of Mind, the contribution of Nicko (McBrain) was tremendous. He really is a great drummer." – Martin Birch talking about Iron Maiden, December 1983.