At the age of 18, Mendes enrolled to study music under Savino de Benedictis and Antonieta Rudge at the conservatory in Santos. Virtually self-taught in composition, he wrote music under the guidance of Cláudio Santoro and Olivier Toni, and attended Ferienkurse fuer Neue Musik in Darmstadt (Germany) in 1962 and 1968. He was one of the signatories of the New Music Manifesto published by the avant-garde art review Invenção in 1963. He was spokesman for the Noigandres group of concretist poets in Sao Paulo. As a result of this taking this stand, he became one of the pioneers in Brazil in the field of concretist music and its random, integral serial and mixed media aspects. He experimented with new graphic markings and materials and incorporated musical action to composition by creating musical theater, or “happenings”. There are entries for his name in the world’s leading encyclopedias and thematic dictionaries, such as Grove’s (United Kingdom), Rieman (Germany), John Vinton’s major Contemporary Dictionary of Music (USA), and countless others. His works have been played on five continents, particularly Europe and the USA. Some of his outstanding pieces: for orchestra – Santos Football Music and Concerto for Piano and Orchestra; for instrumental groups- Saudades do Parque Balneário Hotel, Ulysses em Copacabana Surfando com James Joyce e Dorothy Lamoura, Longhorn Trio, Rimsky; for choirs, Beba Coca-Cola, Ashmatour, Anjo Esquerdo da História, Vila Socó Meu Amor and numerous pieces for piano and vocals. Mendes took a doctoral degree at Universidade de São Paulo, where he taught in the music department of the School of Communications and Arts until his retirement. His book Uma Odisséia Musical (A Musical Odyssey) was published by Edusp. He is an honorary member of the Brazilian Academy of Music and the Association of Latin American Composers of Art Music based in Mexico. He is also a professor and lecturer, and writes for leading magazines and newspapers in Brazil. Mendes was the founder (1962), artistic director and programmer of Festival Música Nova de Santos, the oldest of its kind in America. As a guest professor and composer in residence, he taught at The University of Wisconsin-Milwauke in the position of University Artist 78/79; and as Tinker Visiting Professor, a distinction that only figures such as the Argentine writer Jorge Luis Borges or the Brazilian Haroldo de Campos had received.