GZR is the third installment of published solo works from BLACK SABBATH bassist Geezer Butler. The first project outside of BLACK SABBATH Butler released was the 1995 G//Z/R band. Butler had ventured out of the BLACK SABBATH confines previously in the 80's with various acts. The GEEZER BUTLER BAND of 1985 included guitarist Pedro Howse, vocalist Richie Callison, a native of St. Louis, Missouri (and subsequently to front HEAD EAST), and drummer John Mee. Former PERSIAN RISK vocalist Carl Sentence (later of erstwhile UFO guitarist PAUL CHAPMAN's GHOST and Swiss veterans KROKUS) also operated with Butler. A later line-up had ex-BIRD OF PREY vocalist Kyle Michaels fronting the band, subsequently of MASI. Former WISHBONE ASH and TRAPEZE vocalist Mervyn Spence had been approached but declined.

Sallying back and forth between BLACK SABBATH in the 80's and 90's Butler, a member of OZZY OSBOURNE's band at the time, forged an extremely heavy proposition in 1995. Joining in were FEAR FACTORY vocalist Burton C. Bell. G//Z/R also comprised Bell's fellow American Deen Castronovo (formerly with such diverse acts as WILD DOGS, BAD ENGLISH and HARDLINE) was also part of OZZY OSBOURNE's rhythm section at the time of the album's release.

For the second album, 'Black Science', Bell had opted out due to commitments with FEAR FACTORY. Butler had changed the name of the band to GEEZER for the record's release. The most amazing aspect of the 'Black Science' record was that the songs were influenced by subjects far removed from the usual Heavy Metal clichéd subject matter. A careful listen to the lyrics will pick up references to a multitude of passions close to Butler's heart, including Sci-Fi TV series 'Captain Scarlet', 'Secret Service', 'Dr Who' and 'Fireball XL5' plus Aston Villa Football Club! Under the GEEZER banner, the band put on their inaugural live show opening for LIFE OF AGONY in New York before debuting in the UK on 18th September 1997 at London's Camden Falcon.

Drummer Deen Castronovo, Butler's rhythm partner in the OZZY OSBOURNE band and previously with WILD DOGS and HARDLINE, would completely change musical direction back to mellower material as he landed the most prestigious of AOR drummer's positions in JOURNEY.

Brown contributes guest vocals to ex-TESTAMENT, DEATH, CANCER and OBITUARY guitarist JAMES MURPHY's 1999 'Feeding The Machine' album.

By 2000 Brown was fronting LD/50, a band including bassist Oddie McLaughlin, drummer Jeremy Colson and ex-FORBIDDEN and TESTAMENT guitarist Glen Alvelais. In late 2001 it was announced Brown had joined American crew BEKWENHEIMER.

Although keeping out of the spotlight for a number of years Geezer Butler finally made a return to join OZZY OSBOURNE's band for the 2004 US 'Ozzfest' dates. This move would act as a trigger for a full blown BLACK SABBATH reformation of the original four members. It would then be learned the bassist, revealing fans would detect some Jazz influences in upcoming work, had been spending his time before these shows crafting a new solo album with a working title of 'Ohmwork', once again working with Clark Brown on vocals and Chad Smith on the drums. The latter held a prior tradition with acts such as HEAVEN'S FLAME, MARY BURNS, ANACRUSIS, LONDON CALLING and PAVLOV'S DOG. Now in keeping with tradition, this Tony Wright produced outing, issued in May 2005, would be credited to another new project title of GZR. That same year Pedro Howse featured a guest guitar solo on ex-BLACK SABBATH singer TONY MARTIN's solo album 'Scream', appearing on the track 'Bitter Sweet'.