Since forming in Manchester way back in 1967, Van der Graaf Generator has gone through several phases. The only constant after numerous personnel changes over the years has been singer and guitarist Peter Hammill. Often described as progressive, Van der Graaf Generator likes to define itself as an art rock or free rock group. Their music has been described as cerebral, complex and entrancing. In 2008, VDGG launched the CD Trisector, a work by Hamill and original members Hugh Banton (keyboards) and Guy Evans (drums). A Grounding in Numbers came out three years later.