Working in India's various film industries, international cinema and theatre, Rahman is one of the world's all-time top selling recording artists. In a notable career spanning two decades, Rahman has garnered particular acclaim for redefining contemporary Indian film music and thus contributing to the success of several films. Rahman is currently one of the highest paid composers of the motion picture industry. He is a notable humanitarian and philanthropist, donating and raising money for beneficial causes and supporting charities. Skilled in Carnatic music, Western classical, Hindustani music and the Qawwali style of Nusrat Fateh Ali Khan, Rahman has been noted to write film songs that amalgamate elements of these music systems and other genres, layering instruments from differing music idioms in an improvisatory manner. Symphonic orchestral themes have accompanied his scores, occasionally employing leitmotif. In the 1980s, Rahman recorded and played arrangements on monophonic sound, synonymous with the era of his musical predecessors K.