Theodor Adorno was the most erudite and most challenging of Mahler’s critical apologists. A deeply cultured thinker whose family background represented a coming together of the twin poles of German rationalism and Italian lyricism, he acquired in his youth a vast knowledge of European classical musical repertoire (mostly by playing piano duets), which he deployed in profound critical readings of a wide range of music. His principal statements on Mahler are surveyed here, from early attempts such as “Mahler Today” (1930) – a concise but wide-ranging essay challenging the prevailing view that Mahler was a late Romantic who had been superseded by the modernist trends of the 1920s – to the monograph Mahler: A Musical Physiognomy (1960) and the centenary address that served as its distillation. A distillation of Adorno’s broader project vis-à-vis late capitalism serves as introduction.