"One" became Metallica's first Top 40 hit in early 1989, based almost entirely on the single's gold-level sales -- pop radio certainly wasn't about to play a seven-and-a-half-minute progressive thrash metal epic about an armless, legless soldier deprived of all sensory input. That subject was actually the main character of Dalton Trumbo's anti-war novel Johnny Got His Gun, and the video integrated footage from the film version of the book between plain, gray-toned shots of the band performing in a blank room, with moving shadows coming from slowly rotating fan blades. It matched the song in intensity and definitely gave the message more impact, a probable reason why Metallica had relented on their earlier vow never to cater to MTV by shooting a video (what a difference a few years would make). The muted, tinny production -- co-botched by the band and Flemming Rasmussen -- robs the louder sections of some of their power, but it also gives the song a weird, sick tone, an alien quality which makes it that much more disturbing. After fading in with artillery and helicopter sound effects off in the distance, the song begins with a creepy minor-key arpeggio figure played on a clean-toned guitar; each time the figure repeats, it ends with a stop-start motif played in 2/4 time (in other words, the measure lasts half as long as the ear expects it to). Kirk Hammett contributes a lyrical solo and Lars Ulrich subsequently enters with vicious cymbal accents on the stop-start 2/4 figure, adding menace to the overall mood of melancholy. After Hammett finishes his solo, multiple guitars (even one acoustic) begin to harmonize with and play off of the arpeggios, creating a lush effect similar to what Led Zeppelin achieved through Jimmy Page's multiple overdubs. James Hetfield sings the verses quietly, but on the chorus, the guitar distortion is abruptly kicked on with shattering force, only to disappear after two lines. This cycle repeats, with Hammett offering more tender solo work, until after the second chorus, when another, four-line chorus leads into a new section driven by distorted guitars and simple, harmonized solo melodies. This gradually transforms into a heavier, riff-driven section, with Ulrich pounding a rapid figure underneath. The guitars ring out for a bit, then begin to double the drum pattern for the legendary "machine gun" riff -- the guitars and drums simulate bursts of machine gunfire, stopping and starting to separate the rounds. What's amazing about this riff is that it's played nearly as fast as the gunfire it's mimicking. Hetfield barks out a catalog of the character's disabilities in two parts, giving the song its emotional climax. The spaces between riffs/rounds are then filled in for a slightly new section, in which Hetfield demonstrates why he was the best rhythm guitarist in speed metal -- he maintains the machine-gun pace without stopping to rest again until the end of the song. That's a little while in coming, because Kirk Hammett launches into a manic, blistering solo that caps off the previous lyrical section with unbelievable intensity, while showcasing the opposite side of his playing. Before the song ends, the filled-in riff figure is played through just by itself, stark in its power, after which the music stops as quickly as a respirator can be unplugged. The various sections and components of "One" are seamlessly integrated and flow logically from one to the next, unlike some Metallica epics, which felt like series of good riffs connected without much in the way of transitions. Although bassist Jason Newsted can barely be heard, the rest of the band is firing on all cylinders, at the absolute peak of their powers; it sums up the band's tremendous range of musical expression in one shining epic, and as such is arguably the defining individual moment of their career. "One" has the power to frighten, to disturb intelligently, to awe listeners with its sheer force; it's simply one of the greatest heavy metal songs of all time.