Spiros Mazis creative and critical thinking has always been the starting point of his compositional activity. Most of his works are based upon extramusical ideas that derive from contemporary views of Physics and Mathematics, which are transferred with as much fidelity as possible, to the musical structure. His research is based on exploring the harmonic series and the relations among their partials with a way that he names Multi-harmonic Modes or Multi-spectral Modes. The first work in which he exploits the connection between music and mathematics, was Nine Variations on an Arithmetical, Sonic and Geometrical Drawing for large orchestra, in 1985. He has invented a system of new fingerings for microtonal intervals for brass which can perform just intonation scales with real fingerings. Fifteen of his works have been distinguished in composition contests around the world. His works for orchestra have been performed by the Athens State Orchestra; Greek Orchestra of Colours; Bulgarian String Orchestra Beograska; Italian Symphony Orchestra of Meran; American String Orchestra of Charleston; Louisiana Symphonietta; German Symphony Orchestra of Marburg; Helvetian Orchestra Santa Maria; German woodwinds orchestra from Langenargen; German Symphony Orchestra of Neckarsulm; Bavarian Classic Orchestra and the Brno Philharmonic Orchestra.