Allan Holdsworth (6 August 1946 – 15 April 2017) was a British jazz fusion and progressive rock guitarist and composer.
Holdsworth was known for his estoteric and idiosyncratic usage of advanced music theory concepts, especially in regards to melody and harmony. His music incorporates a vast array of complex chord progressions, often using unusual chord shapes in an abstract way based on his understanding of "chord scales", and intricate improvised solos, frequently across shifting tonal centres. He used myriad scale forms often derived from those such as the lydian, diminished, harmonic major, augmented, whole tone, chromatic and altered scales, among others, often resulting in an unpredictable and dissonant "outside" sound. His unique legato soloing technique stemmed from his original desire to play the saxophone. Unable to afford one, he strove to use the guitar to create similarly smooth lines of notes. He also became associated with playing an early form of guitar synthesizer called the SynthAxe, a company he endorsed in the 1980s.