:This has already been discussed quite some time ago, on the archived talk page, and the answer was simple. Their first studio album is Kill 'Em All, their second is Ride the Lightning, their third is Master of Puppets, fourth is ...And Justice for All, fifth is Metallica, sixth is Load, seventh is ReLoad, eighth is St. Anger, and the ninth is Death Magnetic. Garage Days and Some Kind of Monster were EPs, Live Shit and S&M; were live albums, and Garage Inc. is a cover album.