Otto Klemperer (14 May 1885 – 6 July 1973) was a German conductor and composer. He is widely regarded as one of the leading conductors of the 20th century.

On Gustav Mahler’s recommendation Klemperer became chorus master then conductor at Prague’s German Theatre (1907-10); between 1910 and 1917 he worked at the opera houses of Hamburg, Bremen and Strasbourg; he was musical director at Cologne (1917-24), Wiesbaden (1924-27) and Berlin’s Kroll Opera (1927–31), but left Nazi Germany in 1933, eventually settling in the USA, where he became conductor of the Los Angeles Philharmonic (1933-39).
After a brain tumour operation in 1939 his career faltered until he became director of the Hungarian State Opera (1947-50). In the 1950s and 60s he achieved great success, largely through his association with the Philharmonia Orchestra in London and his recordings for EMI. In 1959 he was appointed the Philharmonia’s ‘conductor for life’. His last concert was in September 1971.