Joseph Rupert Rudolf Marx (May 11, 1882, Graz - September 3, 1964, Graz) was an Austrian composer, teacher and critic.
Marx was born in Graz and pursued studies in philosophy, art history, German studies, and music at Graz University, earning several degrees including a doctorate in 1909. He began composing seriously in 1908 and over the next four years he produced around 120 songs. In 1914 he joined the faculty of the Vienna Music Academy, later becoming the institution's director in 1922. When the school was reorganized as the Hochschule für Musik in 1924 he was appointed to the position of rector, holding that post for three years. Some of his notable students include Johann Nepomuk David, Paul Ulanowsky, Ivana Lang and Hisatada Otaka. From 1931 to 1938 he was music critic for the Neues Wiener Journal and following World War II he was critic for the Wiener Zeitung.
A collection of Marx's criticisms and essays, Betrachtungen eines romantischen Realisten was published in Vienna in 1947. Just before he died he published a book on acoustics, tonality, aesthetics and musical philosophy entitled Weltsprache Musik (Vienna, 1964).
As a composer Marx is chiefly remembered for his vocal music contributions, particularly his more than 150 lieder. Although most of his songs used piano accompiament, about two dozen of them used symphonic accompaniment. His style is characterized by Slavonic and Italian elements, often with an impressionistic kind of lyricism. His output in the 1920s and early 1930s was focused on orchestral works, followed by a period devoted primarily to chamber music for the remainder of his career. In an interview given to Elyse Mach ("Great Contemporary Pianists Speak for Themselves"; Dover Books on Music), Jorge Bolet said that the "Romantic Piano Concerto" by Joseph Marx was his favorite among the great virtuoso concertos because of the enormous show of strength required from the soloist.
Marx died in his home city of Graz, aged 82.