THE blues. Everyone knows about the blues, don't they? It's such a simple music form. All you have to know is three chords on the guitar and suffer from depression. Not so, according to luthier (someone who makes and repairs string instruments) and blues enthusiast Steve Jones. So here they are, the not so bare essentials of the blues. Where do the blues come from? Basically from songs sung by the slaves in the US when they were in the fields or enjoying themselves. Enjoying themselves? Yeah. People often think the blues is only about being sad, but that isn't true. Very often the blues was sung to help forget the situation the slaves were in. In many ways, it was escapism. And musically it's simple? It depends. The basic blues scale is based on the pentatonic scale, but there are all sorts of scales. There are no rules. This is what made it the forerunner of jazz. Anyway, there are several forms of the blues - Memphis, Delta, Texas and North Carolina - and each has its distinctive feel. So which was the form first recorded and when? Delta blues, probably the most eccentric and dissonant form, back in the early '20s. A lot of people say Robert Johnson was the first King of the Blues, but I reckon it was Charlie Patton because he was recorded first. It was just him singing and an acoustic guitar. Back then the blues was called Race Music, and it sold mostly among the black community. After the Depression, once it started to be recorded again, it became known as the blues. And this is when it crossed over into the white community? Not really. In the '40s, Chess Records started to record some artists who were to become big, people like B. B. King, Buddy Guy, John Lee Hooker and Muddy Waters, but the big crossover came in the '60s. There was a big blues revival, especially in England where people like Eric Clapton, Rod Stewart and the Rolling Stones began to play it to white audiences. Was this ''white'' blues a pale copy of the original? Some people say it lacks integrity and it isn't as much from the heart but, like I said, the blues was as much about entertainment as depression, and these bands were entertaining. So where is the blues now? Well, there are still people keeping it alive. It's not so high profile anymore, but there will always be new melodies built around the blues. Essential albums? The Slide Guitar and Legends of the Blues Volume 1 and 2 compilations, Woke Up This Morning, another collection, Rory Block's Ain't I a Woman and Howlin' Wolf, The London Sessions.