Rust in Peace is the fourth studio album by American thrash metal band Megadeth, released on September 24, 1990, by Capitol Records.

Since its release, Rust in Peace has often been named as one of the best thrash metal records of all time, by publications such as Decibel and Kerrang!, and listed in the reference book 1001 Albums You Must Hear Before You Die.

[3] In 1988, Megadeth appeared at the Monsters of Rock festival at Donington Park in the UK, alongside Iron Maiden, Kiss, Helloween, Guns N' Roses, and David Lee Roth.

The band performed to an audience of more than 100,000 people[4] and was soon added to the "Monsters of Rock" European tour, but dropped out after the first show due to bassist David Ellefson's drug problems.

[12] The album title Rust in Peace was inspired by a bumper sticker that Mustaine saw on the back of a vehicle while driving home from Lake Elsinore, California.

[18] It references "Hangar 18", and depicts band mascot Vic Rattlehead and world leaders of the era viewing an alien body.

[21][dubious – discuss] The album features multiple lyrical themes: religion,[22] politics and warfare, as well as Mustaine's personal issues, such as his fight against drug and alcohol addiction,[23] UFO conspiracy theories[24] and even the Marvel Comics character Punisher.

He was dissuaded from taking action to have them removed on the basis that they were part of fund raising activities for "The Cause",[26] explained as something to bring equality to Catholics and Protestants in the region.

[30] Mustaine has revealed that the song, originally titled "Child Saint", was one of his earlier compositions, having been written before his tenure with Metallica (1981–83).

[43] In 1994, the album was certified platinum by the Recording Industry Association of America (RIAA) for shipping one million copies in the United States.

[6] Greg Kot of the Chicago Tribune called it Megadeth's most accomplished album, praising its "instrumental virtuosity, thoughtful lyricism and punkish rage".

[34] Robert Palmer of Rolling Stone wrote that the album is demonstration of how far the "nasty speed thrash" concept can go without being "formulaic and boring".

[39][45] Reviewing the album for Entertainment Weekly, Jim Farber described the music as "sheer velocity, combined with dexterity" and Mustaine's lyrics as "nihilistic whimsy".

[46] Music journalist Kim Cooper also noted the album's maturity and wrote that Rust in Peace "transcended the hard rock genre and raised the bar to a whole new level".

[47] Another positive reaction came from Rock Hard, whose writer Holger Stratmann stated that the record was "pure Megadeth", filled with "razor sharp guitars" and "snotty vocals".

The MusicRadar staff explained that the record saw Megadeth moving "into the big league", while staying true to their intricate sound and lyricism.

[53] In a list compiled by Chad Bowar of About.com, Rust in Peace was placed as the best heavy metal album of the 1990s and named a "thrash masterpiece".

In 2015, satire website The Onion published an article titled "Humanity Still Producing New Art As Though Megadeth's Rust In Peace Doesn't Already Exist".