It's been a blast watching Metallica grow. Now well past their quarter century mark, the band has been together longer than the Beatles, Cream, the Jimi Hendrix Experience, and Led Zeppelin combined. Musically speaking, America's favorite headbangers have always had more to say than your average posse of speed-thrashgrindcore-hardcore metalheads, and it's for this reason Metallica remains heavy metal's most enduring band of brothers.

Founded in Los Angeles by drummer Lars Ulrich and guitarist James Hetfield in 1981, Metallica became a complete band when they enlisted bassist Ron McGovney and original co-guitarist Dave Mustaine. The lineup solidified when the latter duo was replaced by bassist Cliff Burton in March, 1983, and former Exodus guitarist Kirk Hammett that same April. Brandishing an intense Euro-metal vibe, Metallica's first indie album, Kill 'Em All, sold nearly half a million copies, while major-label follow-ups Ride the Lightning, Master of Puppets, ... And Justice for All, plus the more American-sounding Metallica (a.k.a. the Black Album), Garage Days, Load, ReLoad, and, most recently, St. Anger all ranged from gold to triple-platinum sales. Metallica's wildly successful world tours garnered throngs of fans, whose increasing numbers approached, equaled, and perhaps even surpassed (gasp) the venerable Kiss Army.

When it comes to the guitars of Metallica, you almost have to consider Hetfield and Hammett as a single entity. No matter how cool either guitarist sounds on his own, it's their ultra-heavy, tightly-meshed blend of styles and tones that gives the band its unique sonority. The duo's big, dark, sinister-yet-warm sound set new standards for chops and precision among the cutting-edge '80s metal community, whose big five also included Slayer, Anthrax, Metal Church, and Mustaine's band Megadeth. Hetfield and Hammett each sport different styles and spheres of influence- Hetfield grew up listening to Black Sabbath and AC/DC, and later embraced the music of dark crooners Tom Waits, Leonard Cohen, and Nick Cave; Hammett comes from what former GP editor Joe Gore once called the middle ground between the blues-based rock stylings of the '60s and '70s and the speedball diatonicism of the '80s. But the core of Metallica's melodic, harmonic, and, to significant degree, rhythmic musical mayhem lies in how both guitarists play together. With a few exceptions, that chemistry is what I've set out to capture in this lesson. If you're already a fan, you know what to expect. If you're new to the fold, welcome to Metallica boot camp. First, you've gotta ...