One of the things I love about music is discovering "genre defining albums". Albums that started a certain genre of music, sub-categories of heavy metal in my case. RUSH: 2112 defined Progressive Metal, Death: Human defines Progressive Death Metal, Venom: Welcome To Hell defined Black Metal, Helloween: Keeper Of The 7 Keys defined Power Metal, Metallica: Kill Em' All defined Thrash Metal.........and Carcass: Heartwork defined Melodic Death Metal !!!