Guerrilla is the third studio album by Welsh rock band Super Furry Animals. The record was released on 14 June 1999 by Creation Records and peaked at number 10 in the UK Albums Chart. Guerrilla was conceived as a commercial 'pop' album and was produced by the band themselves, as regular producer Gorwel Owen felt exhausted after a busy schedule working for other bands. Recording took place at Real World Studios, Box, Wiltshire in mid-1998 with the group experimenting with a sampler for the first time and writing a number of songs in the studio. The band tried to create a 45-minute long, immediate sounding record, and therefore chose the upbeat songs from the 25 tracks which were recorded during sessions for the album. Guerrilla was chosen as the album's title as a pun on the group's name.

The album features a mix of musical styles and was described as exemplifying the 'nu-psychedelia' musical genre by British music magazine the NME. Singer Gruff Rhys has stated that his lyrics are upbeat and disposable. Critical reception was generally positive with the record appearing in the "Best album of 1999" lists issued by several magazines. It was subsequently ranked at number 311 on the NME'''s list of "The 500 Greatest Albums of All Time". The band were disappointed with the relative lack of success of the album's singles and went on "pop strike" as a result, issuing the 'lo-fi', all-Welsh language Mwng as the follow-up to Guerrilla in May 2000.

Origins and recordingGuerrilla was deliberately conceived as a commercial-sounding 'pop' album; a "jukebox sort of album, where you listen to it and every song is different," according to singer Gruff Rhys. Rhys has said that the band felt they were waging a "sonic war" against average music and "the mainstream" with the record.

The Super Furry Animals had originally intended to work on the album with Gorwel Owen, who co-produced 1996's Fuzzy Logic and 1997's Radiator with the band. According to Rhys, however, Owen felt "burned out" after producing other bands solidly for a year and a half and asked the group to wait until he had chance to rest. The Super Furry Animals were so keen to record that they decided to produce the album themselves. Guerrilla was recorded at Peter Gabriel's Real World Studios in Box, Wiltshire during the middle of 1998. Although Rhys has stated that the group met Gabriel several times during recording, and that they thought he was "a good old guy", Real World was chosen because it was near to the band's homes in Wales rather than because of its association with the former Genesis frontman. Sessions were "much less volatile than usual" according to Rhys, as the five members of the band felt they had to reach consensus over everything because they were producing the record themselves—while recording their previous albums the band would often fall out and shout at each other safe in the knowledge that Owen would act as a mediator and take the final decisions. Bassist Guto Pryce has stated that the band also felt happier during recording sessions for Guerrilla because they had their pets with them at Real World, and were able to relax and enjoy the 1998 FIFA World Cup and the British summer.

During recording, the band used a sampler for the first time and hired many different musical instruments. The group experimented with electronic sounds and wrote several of the album's tracks in the studio, allowing "the music to dictate itself". The song "Wherever I Lay My Phone (That's My Home)" was written around the ringtone of a mobile phone with the rhythm track being based on a sample of bassist Guto Pryce tripping over a lead while Huw Bunford played a note on his guitar. "Some Things Come from Nothing" came from an acid house tune written by keyboardist Cian Ciaran. Samples of Rhys playing an out-of-tune acoustic guitar and Ciaran playing drums were mixed together and the song was "written and recorded simultaneously" by the group. "The Sound of Life Today" is a 22-second sample of "Some Things Come From Nothing" played backwards – an accident that occurred when mixing engineer Chris Shaw rewound the mix and forgot to mute the tape machine. According to Rhys the band gave the track a "really pompous title" so that listeners would expect to hear the meaning of life and instead get just a "collection of noises". "Do or Die", "Fire in My Heart" and "Keep the Cosmic Trigger Happy" were written by Rhys while "The Door to This House Remains Open" developed from a band jam of the Rod Stewart song "Do Ya Think I'm Sexy?" which completely changed over the 30 minutes the group played for. The melody for "Northern Lites" was written by Gruff Rhys several years before the track was released. Reggae and rock styles were tried by the band before they settled on calypso after Rhys wrote lyrics for the song and tried playing along to a preset calypso rhythm track which was on his keyboard. The band added steel drums to the track on the spur of the moment after seeing the instruments "lying around" Real World during recording. The steel drums parts were performed by keyboard player Ciaran, despite the fact he did not know how to play them.

Around 25 tracks were recorded for Guerrilla, with all members of the band agreeing to trim this number down for the final track listing of the record in order to make a 45-minute-long album which was immediate. The group chose the 'up' songs, the "digital songs with more of a constant rhythm", that they had recorded and left off the 'down' tracks to create a positive "brash and light-weight" record—a "disposable pop album that's too good to throw away". According to Bunford, some of the more guitar-orientated songs the group recorded were included on initial track listings and were only left off the record at the last minute in favour of more electronic sounding tracks. Rhys has said that the decision to include "The Teacher" on the album was a decisive moment, as the track is "the most stupid thing on the record"—if a more downbeat song, such as eventual B-side "The Matter of Time", had been included in its place, Guerrilla would have been a much more self-indulgent album. The singer has also stated that the group's "healthy ego problems" would often result in individuals fighting to have some of their own songs removed from the final track listing of the record in favour of songs written by other members. The band chose to sequence the album like a hip hop record, with "Check It Out" as an introduction and "A Specific Ocean" and "The Sound of Life Today" as interludes.

The album's title is pun on the band's name but was also chosen by the group as they felt it had added resonance in the wake of the 1999 NATO bombing of Yugoslavia. Rhys has also stated that the band sometimes flatter themselves that they "take a guerrilla stance outside things, make things that aren't pop, popular in the future". The band added the subtitle "Non violent direct action" to the album's packaging to ensure that no-one could read any "crass, militaristic statements" into the name of the record. The band thought about making a film to accompany the album but ultimately decided that the idea was "too ambitious". They returned to this idea with 2001's Rings Around the World, making music videos for each of the tracks on the record and including them on the album's DVD release.

Musical styleGuerrilla features an eclectic mix of musical styles and has been described by Pitchfork as a combination of the group's techno roots and their more recent "sunny guitar-pop". The NME featured an interview with the Super Furry Animals, several weeks before the release of the album in the United Kingdom, as the lead article in an issue which discussed the "nu-psychedelia" musical genre, which they saw Guerrilla as exemplifying. Gruff Rhys has stated, however, that he sees the album as a quite conventional pop album, and that he associates psychedelia with improvisation whereas Guerrilla was "almost entirely preconceived". The singer has also said that the album is not a radical departure for the group musically, although it is "more groovy and uptempo [...] more textured and punchy" than the band's previous releases, partly due to the mix which creates a "more American sound". Spin stated that the record combines "prog, glam, techno, and garage" and is the "gleeful missing link in the psych-prog continuum". Select stated that the album juxtaposes pop songs with "rambling odities" and is dominated by the "electronic throbs and pulses" of keyboard player Cian Ciaran at the expense of guitarist Huw Bunford. The magazine went on to say that Gruff Rhys's voice anchors the record and gives life to songs which otherwise might seem to be works-in-progress, citing "Chewing Chewing Gum" as an example.

The Melody Maker has described opening track "Check It Out" as a "jazz funk" song which turns into dub after its first minute. The magazine went on to state that the song sums up the album due to its "defacement of symmetry" and disorder, which is also evident on "Do or Die", "The Turning Tide" and "The Teacher", all of which start as pop before ending up "skew