Master of Puppets illustrates why Metallica was one of the most important metal bands ever.After giving birth to thrash with Kill ‘Em All, Metallica began refining their innovations with Ride the Lightning, which added a bit more maturity and compositional quality. Master of Puppets is a much larger step in the same direction, and had the band incorporating more progressive elements into their music. It’d be hard to count the metal bands doing half the pioneering things Metallica was doing.The acoustic, quiet introduction to “Battery” explodes under an aggressive onslaught of hyperkinetic, muscular riffs and thick, heavy arrangements that characterize the entire album. That’s not to say it’s redundant, though. All eight songs are excellent, featuring enough variation of tempo and texture to ensure that they never get boring, which is crucial when some songs extend for eight minutes (“Master of Puppets,” “Disposable Heroes,” “Orion”). Cripes, you could dissect the riffery of the title track and probably create half a dozen normal metal songs. That”s part of Metallica’s appeal: they cram a ton of ideas into their music, but all songs are perfectly crafted without the slightest sense of disjointed songwriting.Speaking of the title track, it in particular sports a dynamic composition, where its middle section diminishes into a quieter, evocative guitar solo (one of the few played by Hetfield) before taking off all over again. “Welcome Home (Sanitarium)” mirrors “Fade to Black” in its progression of intensity. It starts with haunting melodies, turning up the crunch for the chorus, then kicks into high gear with a weighty, fast riff and a glistening lead that carries the song to its vengeful apogee. Hetfield isn’t quite a master lyricist, but for the first time in Metallica’s career, the lyrics were insightful with effective diction. Note the telling and vitriolic “Disposable Heroes” or “Leper Messiah.” Hetfield was never a great singer, but he was a good metal vocalist. Although his ferocity was tempered by youthful pipes, he still managed to convey the viciousness required of music so heavy, so furious.And even when the band eschewed words and singing, they could impress. “Orion” is a marvel of metal songwriting, being an eight minute instrumental with precise, articulate solos (including a short-but-sweet one from the late bassist Cliff Burton) and big, chugging riffs. Most metal bands wrote instrumentals that were three or four minutes long…never eight. But Metallica did it, and they did it well enough to make songs like “Orion” and “To Live Is To Die” (from …And Justice) among my favorite metal instrumentals.Add my voice to the many, many fans who have rated this album five stars (about 362 at the time of this writing). If Master of Puppets isn’t the best metal album ever, it’s very very close.