Metallica's 1983 debut Kill 'Em All laid the foundation for thrash metal with its aggressive musicianship and vitriolic lyrics. The album revitalized the US underground scene, and inspired similar records by contemporaries. The band's second album Ride the Lightning extended the limits of the genre with its more sophisticated songwriting and improved production. The album caught the attention of Elektra Records representative Michael Alago, who signed the group to an eight-album deal in the fall of 1984. Elektra reissued Ride the Lightning on November 19, and the band began touring larger venues and festivals throughout 1985. After parting with manager Jon Zazula, Metallica began working with Cliff Burnstein and Peter Mensch of Q Prime.
Metallica was motivated to make an album that would impress critics and fans, and began writing new material in mid-1985. Lead vocalist and rhythm guitarist James Hetfield and drummer Lars Ulrich were the main songwriters on the album, already titled Master of Puppets. The two developed ideas at a garage in El Cerrito, California, before inviting bassist Cliff Burton and guitarist Kirk Hammett for rehearsals. Hetfield and Ulrich described the songwriting process as starting with "guitar riffs, assembled and reassembled until they start to sound like a song". After that, the band came up with a song title and topic, and Hetfield wrote lyrics to match the title. Master of Puppets is Metallica's first album not to feature songwriting contributions from former lead guitarist Dave Mustaine.
The band was not satisfied with the acoustics of the American studios they considered, and decided to record in Ulrich's native Denmark. Ulrich took drum lessons, and Hammett worked with Joe Satriani to learn how to record more efficiently. Ulrich was in talks with Rush's bassist and vocalist Geddy Lee to produce the album, but the collaboration never materialized because of uncoordinated schedules. Metallica recorded the album with producer Flemming Rasmussen at Sweet Silence Studios in Copenhagen, Denmark, from September 1 to December 27, 1985. The writing of all the songs except "Orion" and "The Thing That Should Not Be" was completed before the band's arrival in Copenhagen. Rasmussen stated that the band brought well-prepared demos of the songs, and only slight changes were made to the compositions in the studio. The recording took longer than the previous album because Metallica had developed a sense of perfectionism and had higher ambitions.
Rasmussen and Metallica did not manage to complete the mixtapes as planned. Instead, the multitrack recordings were sent in January 1986 to Michael Wagener, who finished the album's mixing. The cover was designed by Metallica and Peter Mensch and painted by Don Brautigam. It depicts a cemetery field of white crosses tethered to strings, manipulated by a pair of hands in a blood-red sky. Ulrich explained that the artwork summarized the lyrical content of the album—people being subconsciously manipulated.
Master of Puppets featured dynamic music and thick arrangements. Metallica delivered a more refined approach and performance compared to the previous two albums, with multilayered songs and technical dexterity. This album and its predecessor Ride the Lightning followed a similar track sequencing: both open with an up-tempo song with an acoustic intro, followed by a lengthy title track, and a fourth track with ballad qualities. Although both albums are similarly structured, the musicianship on Master of Puppets is more powerful and epic in scope, with tight rhythms and delicate guitar solos.
The songs explored themes such as control and the abuse of power. The lyrics describe the consequences of alienation, oppression, and feelings of powerlessness. Author Ryan Moore thought the lyrics depicted "ominous yet unnamed forces of power wielding total control over helpless human subjects". The lyrics were considered perceptive and harrowing, and were praised for being honest and socially conscious by writer Brock Helander. The compositions and arrangements benefited from Burton's classical training and understanding of harmony.
The album opened with "Battery" a track that refered to angry violence, as in the term "assault and battery". Some critics contended that the title actually refers to an artillery battery, and interpreted it as "Hetfield singing of a war tactic as the aggressor" personifying destruction. The song began with bass-heavy classical guitars that build upon multitracked layers until they are joined by a sonic wall of distorted electric guitars, "Master Of Puppets" the iconical single featured lyrics from the point of a voice of a personification of addiction and it was about cocaine addiction. The song consisted of several riffs with odd meters and a cleanly picked middle section with melodic solo. The song shared a similar structure with "The Four Horsemen" from the band's first album: two verse-chorus sets lead to a lengthy interlude to another verse-chorus set, the song closes with a fade-out of sinister laughter
"The Thing That Should Not Be" was inspired by the Cthulhu Mythos created by famed horror writer H.P. Lovecraft, with notable direct references to The Shadow over Innsmouth and to Cthulhu himself, who is the subject matter of the song's chorus. It is considered the heaviest track on the album, with the main riff emulating a beast dragging itself into the sea. The Black Sabbath-influenced guitars are down-tuned, creating slow and moody ambience. "Welcome Home (Sanitarium)" the song's subject matter was about madness and served as a metaphor for honesty and truth, and it was based on Ken Kesey's novel One Flew Over the Cuckoo's Nest and conveyed the thoughts of a patient unjustly caged in a mental institution. "Disposable Heroes" is an anti-war song about a young soldier whose fate is controlled by his superiors. With sections performed at 220 beats per minute, it is one of the most intense tracks on the record.
The syncopated riffing of "Leper Messiah" challenged the hypocrisy of the televangelism that emerged in the 1980s. The song describes how people are willingly turned into blind religious followers who mindlessly do whatever they are told. The 136 beats per minute mid-tempo riffing of the verses culminates in a descending chromatic riff in the chorus; it increases to a galloping 184 beats per minute for the middle section that climaxes in a distorted scream of "Lie!". "Orion" was a multipart instrumental highlighting Burton's bass playing. It opens with a fade-in bass section, heavily processed to resemble an orchestra. It continues with mid-tempo riffing, followed by a bass riff at half-tempo. The tempo accelerates during the latter part, and ends with music fading out. Burton arranged the middle section, which features its moody bass line and multipart guitar harmonies.
And finally "Damage, Inc." ranted about senseless violence and reprisal at an unspecified target. It starts with a series of reversed bass chords based on the chorale prelude of Bach's "Come, Sweet Death". The song then jumped into a rapid rhythm with a pedal-point riff in E that Hammett says was influenced by Deep Purple.
Master of Puppets was hailed as a masterpiece by critics outside of the thrash metal audience and cited by some as the genre's greatest album. The band had redefined heavy metal with the technical skill and subtlety showcased on the album, which he described as "the sound of global paranoia". The album was the one that finally put Metallica into the big leagues where they belong". The album became thrash metal's first platinum album and by the early 1990s thrash metal successfully challenged and redefined the mainstream of heavy metal, until now, the album is widely accepted as the genre's most accomplished album, and paved the way for subsequent development.
