`The thing about jazz is it doesn't have `the big message' - we don't generally sing songs about heroin addiction or my-girlfriend-just-left-me, but musically we do convey those same emotions."

Gerry Godley runs the Improvised Music Centre, an organisation which promotes jazz music in Ireland. This Sunday, May 9th, the centre is running OpenJazz 1999, its second annual open jazz day, in Dublin's Temple Bar. "We don't want to be what you might call the custodians of such a beautiful secret. The point of the open day is to share the joy of jazz," he says. Nonetheless, Godley is conscious of the fear and ignorance surrounding jazz. As recently as the 1950s, in Ireland and elsewhere, it was known as "the devil's music".

"Jazz is not that telegenic. The jazz musicians of the 1960s weren't as visual as Elvis or Mick Jagger and, as the role of television in promoting popular culture grew, jazz was gradually sidelined. It was superseded by rock 'n' roll - which, incidentally, has roots in jazz. "Now you just don't hear it in the same way you hear mainstream pop music. So, when people do hear it, it sounds very unfamiliar." Godley believes it is this unfamiliarity which makes jazz seem so intimidating.

"All music is a language and, like any language, we have to be able to understand to relate. I think the fear of jazz comes from a lack of understanding of its modus operandi." Essentially, he says, jazz is very simple. "The basic philosophy is theme and improvisation. It isn't complicated, but the spontaneity which comes with jazz is something you no longer hear in popular music. Pop music does contrive to be free, but actually it is very structured. A jazz musician is after musical freedom, interacting with other musicians in a very free way - so that you don't have to think, but the music just flows."

Used to the more formulaic and rigid sound of pop music, people tend not to recognise the elements of jazz which can be heard in all sorts of music we listen to every day. "The Lauryn Hill album would be a good example of music which uses a lot of jazz samples, but there are less obvious ones like Robbie Williams's Millennium, which was written by a jazz musician, John Barry. Lots of film scores are jazz-based - the famous tune to the Pink Panther is a jazz tune written by Henry Mancini.

"You get jazz elements in hip-hop - an awful lot of what's used for the breaks is jazz. And it has its influences in dance music as well. Up until the 1940s jazz was always played for dancing. Charlie Parker added new phrases to the jazz vocabulary which moved it on from dance music, but a powerful groove is still at the heart of the best jazz. "What we call funk was practically invented by Miles Davis in the late 1960s. Walk on the Wild Side by Lou Reed has a straight jazz saxophone solo in it, and the work of more current bands like The Divine Comedy is full of jazz references.

"What gives jazz that distinct sound involves the instrumentation, the phrasing and a groove which gets your foot tapping, usually with that sort of swinging rhythm." Jazz was the pop of its day. "But it declined from view in a similar way to how something like punk is no longer fashionable. In a way jazz has been a victim of the dumbing-down of culture - and this idea that has developed which is anything with any depth is bad. "But jazz, like any art form, has to evolve or it dies." Although it's still not top of the pops, sales indicate the popularity of jazz is rising; it was last year's fastest- growing genre in Irish record shops. It can be heard on telly in ads and TV-show themes, and in trendy restaurants and cafes.

While it can be hard to make a living as a jazz musician, jazz players enjoy what Godley calls "a lot of mobility. Most of the musicians I know in Riverdance are jazz musicians, for example. You also don't have to be young to do well as a jazz player - in fact, jazz musicians usually peak as players in their 50s. "But in Ireland there aren't enough opportunities to play, and we are out of step with other EU countries in terms of education. It is at last possible to play jazz for Junior and Leaving Cert. Although there are excellent courses available at Newpark Music Centre in Dublin, there is still no third-level qualification in jazz."