Jazz as we know it now grew from a form of music that was passed directly from musician to musician without too much theory being involved. Jazz guitar theory is a collection of ideas and traditions that has grown over the decades of jazz playing.

The original jazz guitar players did not need theory. They needed to know their guitars well enough to be able to provide part of the rhythm for other instruments in the band or to play solos if they were needed. The nature of guitar playing in jazz bands varied over the years and depended on whether the guitarist was in a big band or a small group.

Jazz guitar theory is the product of the need for jazz guitar players to communicate musical ideas to one another. To pass these ideas on a guitarist needed to be able to read standard musical notation and, as jazz guitar playing became more sophisticated, he needed the technique to play the exotic barre chords that became the norm in jazz guitar music.

A part of jazz guitar theory is what we could loosely call traditions of jazz - ways of approaching music that have become standard practice for jazz players. None of these traditions is set in concrete, but the use of the electric archtop guitar has become widespread over the years as is the use of barre chord voicings rather than open chords.

If you learn jazz guitar theory you will learn to rely on the seventh and third notes of a chord and how interest can be added by the use of the ninth, eleventh or thirteenth notes. These notes may be totally foreign to the original melody the guitarist is improvising over, but jazz guitar players have the work of guitarists from previous generations to draw on when they make use of these unusual voicings.

A big part of jazz guitar theory is the types of techniques used to express musical feelings. Jazz guitar players have their own strumming patterns and chord progressions that may vary greatly from the ways of playing the original genre they might be interpreting. Also, although rock and blues guitar players of the past thirty or so years have left their mark on jazz, there is a tendency among jazz guitarists to use electronic effects rather sparingly.

To examine the basis of jazz guitar theory we need to be aware of the founders of modern jazz guitar playing, like Wes Montgomery, Jim Hall, Barney Kessel, Joe Pass and Herb Ellis as well as the founders of jazz guitar tradition like Django Reinhardt and Charlie Christian. Jazz guitar theory has been shaped by modern players who have departed from tradition, such as John McLaughlin, Al Di Meola and Pat Metheny.