U.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 U.S. 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 U.S. 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 U.S. (11 U.K.), 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 U.K. where it landed on a 19 (77 U.S.). After Mechanix (1982) and its U.K. 8 (82 U.S.), 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 U.K. 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 U.K. 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 withVinnie Moore and Jason Bonham respectively, with Paul Raymond (ex-Michael Schenker Group) being added for keyboards on You Are Here (2004).
Footnote: The album 3D Perspective released in 1997 was not released by this U.F.O. but another unrelated act using the same name.