Themes

Through the late 1970s and early 1980s, pioneering heavy metal bands often included outlandish and fantasy-inspired lyrics, giving them an escapist quality. Iron Maiden frequently based songs on mythology, fiction and poetry, like in "Rime of the Ancient Mariner" (based on the Samuel Taylor Coleridge poem of the same name), or the majority of their 1982 release Piece of Mind. Other examples include Black Sabbath's "Fairies Wear Boots" and "The Wizard," Megadeth's "The Conjuring" and "Five Magics," and Judas Priest's "Dreamer Deceiver."

As the genre developed, thematic content was among the things that helped define various subgenres of heavy metal. Popular Glam metal bands of the 1980s like Motley Crue or Twisted Sister had lyrical content revolving around themes of teenage life and social issues. At the same time, other artists were revolving their themes around war, nuclear annihilation, environmental issues, and political or religious propaganda, like Black Sabbath's "War Pigs", Ozzy Osbourne's "Killer of Giants", Metallica's ...And Justice for All, Iron Maiden's" 2 Minutes to Midnight", Accept's "Balls to the Wall" and Rage Against the Machine's entire catalog. Death is also a predominant theme in heavy metal, featuring in the lyrical content of artists such as Black Sabbath, Metallica, W.A.S.P.

The themes of darkness, evil, power and apocalypse are language components for addressing the reality of life's problems. In reaction to the "peace and love" hippie culture of the 1960s, heavy metal developed as a counterculture, where light is supplanted by darkness and the happy ending of pop is replaced by the naked reality that things do not always work out in this world. This dark thematic content is a target of critics, whom accuse the genre of glorifying negative aspects of reality.

As with much popular music, visuals and images are part of heavy metal. Album covers and stage shows are as much a part of the presentation of the material as the music itself, though seldom exceeding the music in priority. A heavy metal band's "image" is associated with the thematic content of their lyrics, and is expressed in the artwork on the album, the set of the stage, the tone of the lyrics, and the clothes of the band, in addition to the sound of the music.

Heavy metal musicians have often tried to associate lyrics and themes that match with the connotative and suggestive atmospheres conveyed by music. Progressive rock bands such as Emerson, Lake & Palmer and Yes had already explored this dynamic before heavy metal evolved. As heavy metal uses apocalyptic themes and images of power and darkness, the ability to successfully translate verbal ideas into music is often seen as critical to its authenticity and credibility. An example of this is the album Powerslave by Iron Maiden. The cover is of a dramatic Egyptian scene and many of the songs on the album have subject matter requiring a sound suggestive of life and death, including a song entitled "The Rime of the Ancient Mariner," based on the poem by Samuel Taylor Coleridge. Iron Maiden bassist Steve Harris has cited progressive rock bands[17] such as Rush and Yes as influences, and it should be noted that the 1977 Rush album A Farewell to Kings features the eleven-minute "Xanadu," also inspired by Coleridge and pre-dating the Iron Maiden composition by several years.