Gárdonyi's short organ piece "Mozart Changes", composed for the 1995 "OK MOZART" International Festival in Bartlesville, departs from the theme of the finale of Mozart's last piano sonata in D major, K. 576, and treats it to changes using elements of jazz. Gárdonyi´s recent organ piece LIFT HIGH THE CROSS has been premiered by his son Daniel Gárdonyi on 10 February 2019 at St Albans in Hardheim. In 1979 Gárdonyi received the prize for composition of Bavaria. In June 2000 he was awarded an honorary doctorate by the Debrecen Reformed University in Hungary. In 2011 he was awarded a medal of honor by the president of Hungary. One major area of Gárdonyi's research is the harmony of the 19th and 20th century (Liszt, Debussy, Skriabin and Messiaen), resulting in a book he published together with Hubert Nordhoff, "Harmonik" (Harmony). The book was translated to Hungarian. He also researched the relation between composition, interpretation, analysis and improvisation. He published a book on counterpoint, taking Bach's fugal structures as examples. The book was translated to Italian. Music and books were published by Möseler, Walhall, Ostinato, Zimmermann, Merseburger, Bärenreiter, Heinrichshofen and Schott. Gárdonyi edited various works by César Franck and his father Zoltán Gárdonyi, such as the three motets , chamber music and compositions for organ.