Most people either love or hate Frank Zappa - if they've heard of him at all. To much of the press, he's incomprehensible. To his lyrical targets, he's obnoxious. To fans, he's a musical genius whose every recorded note deserves a place in their collections. To disbelievers, he's not funny enough, too much - or not enough - of a 'rock' star, too political, too 'jazzy', too 'classical' or too crude.

At the time of his death in 1993 from prostate cancer, Zappa had released almost 60 albums. A huge number of musicians, including Captain Beefheart, Lowell George, Steve Vai, George Duke, Jean-Luc Ponty, Adrian Belew, The Brecker Brothers, Eddie Jobson and Warren Cucurullo, had worked closely with him over the years.

Born in Baltimore, Maryland in 1940, Frank Vincent Zappa grew up with an interest in chemistry and music. The former led to suspension from high school after a series of incendiary experiments. Following unsuccessful careers as a Hollywood film score writer, advertising copywriter and greetings card designer, he finally followed his musical muse by joining The Soul Giants in 1964.

The Soul Giants promptly became The Mothers, then (at their record company's insistence) The Mothers of Invention and the weird-beard psychedelic freak out began. In fact, their 1966 debut was called Freak Out, and was only the second double album ever released. Single albums could never really contain Zappa's sprawling imagination.

Neither could the stage. During a six month residency at the Garrick Theatre in London in 1967, the Mothers' show included hurling rotting vegetables and spitting whipped cream at stuffed animals. Jimi Hendrix joined them on stage. As did the US Marines: a squad were once invited to demonstrate their killing techniques on a doll.

In 1971, Zappa produced 200 Motels, a film (and album) featuring Ringo Starr (as a Zappa lookalike) and Keith Moon (as a nun). The supporting stage show was famously banned from the Royal Albert Hall on the grounds of 'obscenity'. Also in 1971, the Mothers' equipment was destroyed in a fire caused by a carelessly-hurled firecracker at the Montreux Festival - an event celebrated by Deep Purple's 'Smoke On The Water'.

Zappa's musical direction was a synthesis of his love of R&B, doo-wop, modern classical (particularly Stravinsky) and experimental electronica (Varese). His eclecticism led him to consider himself a composer rather than simply a songwriter or guitarist - his 1967 album, Lumpy Gravy, for example, anticipated sampling. After discovering the 18th-century Baroque composer Francesco Zappa, Francis recorded an album of his work using a computerised synclavier. His own works have been performed by the London Symphony Orchestra, the Ensemble Inter Contemporain and The Kronos Quartet.

Zappa's lyrical preoccupations were equally wide-ranging, if occasionally scatalogical. Often condemned for their scurrilous nature, political incorrectness or surrealism, his lyrical targets have included politicians, evangelists, yuppies, gays, Jewish princesses, truck drivers, groupies and, most famously, valley girls. "My insensitivity is pretty evenly spread around," he said in 1993. Though often mistaken for a hippie because of his appearance, Zappa's views on the Dionysiac counterculture can be inferred from his consistent anti-drug stance (always excepting coffee and cigarettes).

Thing-Fish, a concept album from 1984 is often described as Zappa's most offensive and difficult release. Originally intended as an off-Broadway musical, its themes are homophobia and racism. Increasingly concerned about the power of the politically-motivated parents' 'concern' group the PMRC, Zappa testified before the US Congress in 1985 in an attempt to prevent the censorship of the music industry. The Grammy he won for Best Rock Instrumental in 1987 (for Jazz From Hell) may have been awarded in acknowledgement of this stand. The music industry, anxious to obtain government support for its blank tape levy, had caved in.

The extent of Zappa's political influence was demonstrated by longtime fan President Vaclav Havel when he appointed Frank US Cultural Liaison to the Czech Republic in 1990. The American Government exerted pressure to have the appointment rescinded. Then, in 1991, Zappa announced that he was going to stand as an independent candidate in the next Presidential elections. Death threats soon followed.

What stands out most about Zappa is his passion for perfection. He demanded the highest standards from his musicians and, onstage, conducted them as strictly as any classical martinet. He used the finest recording equipment, building a state-of-the-art home studio (the Utility Muffin Research Kitchen). Neither pure art nor utter trash, his music describes the absurdities and injustices of life. Never merely a clown nor a composer, he was always entertaining.