.F.O. started out under the name of Hocus Pocus by Phil Mogg (vocals), Pete Way (bass), Andy Parker (drums) and Mick Bolton (guitar). After getting a contract with indie 'Bacon Records' they changed their name and got a surprising amount of success in Japan and Germany for their debut albums U.F.O. and U.F.O. 2 - Flying (both 1971). After U.F.O.: Live (1972), a live set of their recent visit to Japan, Michael Schenker replaced Bernie Marsden on guitar, who was originally a replacement for Mick Bolton. Phenomenon came and went in 1974 featuring the new members heavily, but the follow-up Force It (1975) managed to make a US 71 with temporary member Paul Chapman, but they returned to a quartet quickly after when the guitarist left to join Lone Star. The album did as well as it did because of Schenker who's flying-v guitar fingering made the talk of the town. The follow-up No Heavy Petting (1976) was far less impressive affair and was the debut for keyboardist Danny Peyronel (ex-Heavy Metal Kids).
Lights Out was a much more impressive affair, making top 30 in the US The album now featured Paul Raymond (ex-Savoy Brown) taking over the keyboard slot. Too Hot To Handle and Alone Again Or held the record high on people's minds, with Only You Can Rock Me becoming a classic Hard Rock anthem. After the live set Strangers In The Night (1979) Schenker decided to leave to rejoin the Scorpions and was replaced by Paul Chapman. By the follow-up album, it was clear that the only thing flying away in U.F.O. was the band members themselves for after No Place To Run (1980), an album that made respectable grades in the charts on both sides of the pond with a 51 in the US (11 UK), Raymond now left and Neil Carter replaced him for the follow-up Wild, The Willing And The Innocent (1981), an album that also made respectable grades, especially in the UK where it landed on a 19 (77 US). After Mechanix (1982) and its UK 8 (82 US), the act must have thought the tough times were behind them, but it was not to be. Pete Way was the next to leave to form his own Fastway, Waysted act and eventually joining Ozzy Osbourne. Making Contact (1983) made contact only in the UK at 22, but Mogg couldn't handle his workload and suffered a breakdown on stage while on tour. Upon returning he shut the act down suddenly.
In 1984 Mogg resurrected the act with Paul Raymond returning, along with punk recruit Paul Gray (ex-Damned; bass), Jim Simpson (ex-Magnum; drums) and Atomik Tommy M. (guitar) to release Misdemeanor (1985), an album that once-again only charted in the UK But shortly later, Raymond left to be replaced with David 'Jake' Jacobson for the opposite activity, Ain't Misbehavin' (1988), and once-again the act split up.
But once again the act was fired up soon after, this time with Mogg and Way returning and adding Laurence Archer (ex-Grand Slam; guitar), Clive Edwards (ex-Wild Horses; drums) and Jim Davis (keyboards) to release High Stakes And Dangerous Men (1992) to little public care. That effort was followed by two more albums, Lights Out In Tokyo (1993; a live set) and Walk On Water (1995), with each meeting a similar fate. Old crony Michael Shenker (ex-Scorpions) was back in the fold on the former album replacing Archer. This album also saw a new member in the form of Andy Parker also step in to take over drums.
Mogg and Way went on their own to release Edge Of The World (1997) and Chocolate Box (1999) to similar success. But apparently these guys couldn't get the message and reformed U.F.O. again to release Covenant (2000), with Aynsley Dunbar (ex-Null) now on drums. Schenker would be out again after the release of Sharks in 2002, not to mention Dunbar, both of whom were replaced with Vinnie Moore and Jason Bonham respectively, with Paul Raymond (ex-Michael Schenker Group) being added for keyboards on You Are Here (2004).
The Monkey Puzzle, was released in 2006.
Andy Parker returned in early 2007 after recovering from leg surgery. On the 2008 tour, Pete Way was unable to get a work visa to enter the United States, Rob De Luca (Sebastian Bach's band/Of Earth/Spread Eagle) filled in.
The Visitor (2009) followed and was accompanied with a tour of the UK, sans Pete Way, who was suffering from a medical condition. Bass tracks on The Visitor were played by Peter Pichl; Pete Way was not credited as a band member on the album, nor was any other bassist. The album saw UFO's return to the UK Top 100 album charts for the first time in 15 years.
In July 2009, UFO released a six-CD live concert box set, containing recordings of six concerts between 1975 and 1982, as well as previously unreleased live songs.
On their 2011 tour, Barry Sparks played bass.
Seven Deadly (2012) with Lars Lehmann on bass, saw UFO reach chart status again.
In 2011, former band members Danny Peyronel, Laurence Archer, and Clive Edwards teamed up with bassist Rocky Newton (ex-McAuley Schenker Group) to form the band X-UFO. In live performances, X-UFO played sets of vintage UFO songs, later renamed House Of X to perform their own material. Their eponymous album was released on 24 October 2014.
A Conspiracy of Stars was released in February 2015, The Salentino Cuts followed in 2017.
Footnote: The album 3D Perspective released in 1997 was not released by this U.F.O. but another unrelated act using the same name.