Carlos Kleiber (3 July 1930 – 13 July 2004) was a German-born Austrian conductor, who is widely regarded as among the greatest conductors of all time. The son of the conductor Erich Kleiber, he was particularly known for the Romantic repertoire. John Rockwell notes writes: "A fabled perfectionist, he demanded long hours of rehearsal as his reputation grew and allowed him to obtain such concessions. But he made all that work pay off in performances that blended exactitude with impassioned spontaneity."

Kleiber was born as Karl Ludwig Bonifacius Kleiber in Berlin in 1930, the son of the eminent Austrian conductor Erich Kleiber and American Ruth Goodrich (née Baumgardner, 1900 – 1967), from Waterloo, Iowa. In 1935, the Kleiber family emigrated to Buenos Aires and Karl was renamed Carlos. As a youth, he had an English governess and grew up in English boarding schools. He also composed, sang, and played piano and timpani. While his father noticed his son's musical talents, he nevertheless dissuaded Carlos from pursuing a musical career: "What a pity the boy is musically talented", wrote Erich to a friend.

Carlos first studied chemistry at ETH Zurich but soon decided to dedicate himself to music. He was répétiteur at the Gärtnerplatz Theatre in Munich in 1952 and made his conducting debut with the operetta Gasparone at Potsdam theatre in 1954. From 1958 to 1964 he was Kapellmeister at the Deutsche Oper am Rhein in Düsseldorf and Duisburg, and then at the Opera in Zurich from 1964 to 1966. Between 1966 and 1973 he was first Kapellmeister in Stuttgart, his last permanent post. During the following years, he often conducted at the Bavarian State Opera in Munich.

During his time at Düsseldorf his operatic repertoire included Giuseppe Verdi's La traviata, Rigoletto, I due Foscari and Otello, Giacomo Puccini's La bohème and Madama Butterfly, Richard Strauss' Daphne and Der Rosenkavalier, Jacques Offenbach's Les Contes d'Hoffmann plus several of his operettas, Franz Lehár's The Merry Widow, Engelbert Humperdinck's Hansel and Gretel, Igor Stravinsky's Oedipus Rex and Ruggero Leoncavallo's Edipo re. At Zurich he conducted Verdi's Falstaff and Bedřich Smetana's The Bartered Bride for the first time.

During his freelance career, Kleiber restricted his conducting appearances to select occasions. He made his British debut in 1966 with a performance at the Edinburgh Festival of Alban Berg's Wozzeck, a work whose premiere his father had conducted in 1925. Kleiber's repertoire at the Royal Opera House included Der Rosenkavalier, Elektra, La bohème and Otello. He made his Bayreuth debut in 1974 conducting Richard Wagner's Tristan und Isolde.

His American debut came in 1978 with the Chicago Symphony Orchestra, where he again conducted in 1983, his only US orchestra appearances. His Metropolitan Opera debut was in 1988, conducting La bohème with Luciano Pavarotti and Mirella Freni. In 1989, following Herbert von Karajan's resignation from the Berlin Philharmonic, Kleiber was offered, but declined, the opportunity to succeed him as music director. He returned to the Met in 1989 to conduct La traviata, and in 1990 for Otello and Der Rosenkavalier.

Kleiber kept out of the public eye and apparently gave one interview in his lifetime, contrary to reports that he never gave any. After he resigned from the Bavarian State Opera, his appearances became less frequent and he made only a few recordings.

Most of these studio recordings are highly regarded; they include Ludwig van Beethoven's fifth and seventh symphonies with the Vienna Philharmonic, Johannes Brahms's Symphony No. 4 and Franz Schubert's third and eighth ("Unfinished") symphonies, also with the Vienna Philharmonic, recordings of Dvořák's Concerto for piano and orchestra with Sviatoslav Richter, Carl Maria von Weber's Der Freischütz, Johann Strauss' Die Fledermaus and Giuseppe Verdi's La traviata. His last studio recording was Richard Wagner's Tristan und Isolde with the Staatskapelle Dresden. Recording sessions began in 1980. Kleiber left before they were completed, but since a musically complete performance had been set down, Deutsche Grammophon released it, much to Kleiber's anger.^{[citation needed]}