Lyle Mays, the Grammy-winning jazz keyboardist best known for his work with the Pat Metheny Group, has died. He was 66.

Born in Wausaukee, Wis., in 1953, Mays took up music early and was shaped by the work of Bill Evans and Miles Davis. In the 1970s, he co-founded the jazz-fusion group with Metheny and served as a performer, composer and arranger in the band. The group’s innovative style incorporated rock, contemporary jazz, world music and more.

New York-based jazz vocalist Aubrey Johnson, niece of Mays, shared the news of his passing on Monday.

“It is with deep sadness that I share that my uncle, Lyle Mays, passed away this morning in Los Angeles surrounded by loved ones, after a long battle with a recurring illness,” Johnson wrote. “Lyle was a brilliant musician and person, and a genius in every sense of the word. He was my dear uncle, mentor and friend, and words cannot express the depth of my grief. From his family, thank you for loving him and his music.”

Mays composed and arranged nearly all of the Pat Metheny Group’s music, and was rewarded with 11 Grammy Awards. In addition to the keyboard, he also occasionally played electric guitar and trumpet in the band. Mays’s own work earned him four more Grammy nominations.

“Lyle was one of the greatest musicians I have ever known,” Metheny said of his former bandmate. “Across more than 30 years, every moment we shared in music was special. From the first notes we played together, we had an immediate bond. His broad intelligence and musical wisdom informed every aspect of who he was in every way. I will miss him with all my heart.”

Beyond his work with the Pat Metheny Group, Mays was also a sideman for albums by numerous jazz, rock and pop artists, including Joni Mitchell, Rickie Lee Jones and Earth, Wind & Fire. He composed and recorded music for children’s records, and he helped compose the music for several film soundtracks.Tributes poured in throughout the week from jazz musicians, journalists and many others.

“Lyle Mays swept me away like no musician in my lifetime, with the possible exception of his writing partner Pat Metheny. Mays tapped into something dazzlingly beautiful, something full of quiet power, something that spoke directly to the souls of all who heard it,” musician Don Breithaupt said in a Facebook post.

“The music Pat Metheny and Lyle Mays made together is a staple of the world,” said Christian McBride.

“His music gave me great joy and inspiration,” wrote Kurt Rosenwinkel.

In lieu of flowers, Mays’s family has asked that contributions be made to the Caltech Fund.