Hermeto Pascoal, the eccentric, prodigiously prolific Brazilian composer and self-taught multi-instrumentalist who rose from a childhood of rural privation to become a favorite of jazz musicians and audiences around the world with a taste for the unpredictable and adventurous, has died. He was 89. .

His family announced his death on his official social media page on Saturday night. The statement did not provide a cause of death or say when or where he had died.

Known in Brazil as “The Sorcerer” and “The Mad Genius,” Mr. Pascoal affected a wild man’s appearance: He had long, unkempt hair, a thick beard and a childlike demeanor. But he was passionately serious about playing and composing music.

He wrote more than 2,000 instrumental pieces, many with quirky time signatures or harmonies, and orchestrated or arranged hundreds more songs for others, including jazz luminaries like Miles Davis, who once described Mr. Pascoal as “one of the most important musicians on the planet.”

Mr. Pascoal’s primary instruments were the piano and the flute. He also played tenor and soprano saxophones, guitar, drums, accordion, euphonium and a variety of other keyboard, reed, brass and percussion instruments — and often supplemented them, to the delight of audiences, with everyday objects whose capacity to create music only he seemed able to imagine.