(Book). Metallica, the seventh-biggest recording act in American history, are consummate musicians but it wasn't always that way. A significant proportion of their playing expertise was acquired from a pivotal three-year period in their history 1983 to 1986 during which their music, a potent variant of thrash metal, evolved from garage-level to sophisticated, progressive heights thanks to the teachings of their bass player, Cliff Burton. The San Francisco-raised...