Haas was born in Stuttgart on March 3, 1931. He exhibited unusual talent as a young child, though the pianist himself was reluctant to claim he was extraordinarily gifted. Still, he might have developed even sooner but for the exigencies brought on by the war in his homeland. He enrolled at the Stuttgart Academy of Music in 1947, where he took instruction on piano from Lilli Kröber-Asche, who was known for her Mozart
interpretations. Shortly after leaving the Stuttgart Academy in 1954, he traveled to Saarbrücken for two years of study with Walter Gieseking
, whose interest in the music of Debussy
may well have steered Haas toward the French master's works. It was during this time that he launched his career with a critically well-received recital (1955) in his native Stuttgart. From 1956 on, Haas toured Europe and quickly developed a reputation for his Debussy
interpretations. Following a 1958 Paris concert, Philips executive Igor Maslowski signed the pianist to a multi-year contract with his Dutch label. The partnership worked well for both, as evidenced by Haas' numerous discographic successes, including his Debussy
complete works edition, which was awarded a Grand Prix du Disque in 1970, and his Ravel
recordings, which given an Amsterdam Edison Prize also in 1970.
Though Haas began recording in the late '50s, most of his activity in the studio dates to the 1960s. His 1960 recording of Chopin
Waltzes (14) garnered much critical acclaim, even in the United States where it received a rave review in the January 1961 issue of High Fidelity. On tour abroad, he generally drew favorable reviews as well, such as his November 1967 London recital at Wigmore Hall and his July 1970 Milan concert, to name but two. Haas was known to have a broad repertory, but beginning in the latter 1960s, he expanded it to include an even greater range, with works like Prokofiev
's Piano Sonata No. 4. Later, he added that master's Sonata No. 2 to his repertory, as well as compositions by other Russian composers, including Kabalevsky
. By the mid-'70s, Haas' career was in full bloom, with appearances in some of the most prestigious concert halls in Europe and turning out recordings that routinely garnered critical acclaim. Like the American pianist William Kapell
, however, his career ended abruptly and tragically: Haas was killed on October 11, 1976, in a accident near Nancy, France, when his automobile collided with a truck. Many of the pianist's recordings are still available via reissue, most on the Philips label.