When Metallica unleashed Master of Puppets in 1986, the metal world was effectively blown away.

The album is fast, technical, catchy and perfectly written.

Producer Flemming Rasmussen worked closely with the band to overcome technical hurdles.

James Hetfield achieved some of his higher harmonies with tape tricks, but had difficulties singing high notes.

The album's legendary status is due in part to its legendary sound, which was engineered for perfection.

Longtime metal producer Eyal Levi explained how Metallica recorded some parts slowed down and then sped up the analog tape in playback, achieving a level of precision and aggression that the speed of the music demanded.