One of the best of improvised violin & viola, Leroy Jenkins was a member of Chicago's musicians collective AACM, co-formed Creative Construction Company (with Anthony Braxton) and the incredible out-jazz protest trio Revolutionary Ensemble (with Sirone and Jerome Cooper--check out Vietnam on ESP-Disk and Manhattan Cycles on India Navigation). He also worked with Alice Coltrane, Cecil Taylor, Muhal Richard Abrams, Rashied Ali, the JCOA, Andrew Cyrille, Albert Ayler, Archie Shepp, Frank Lowe, Henry Threadgill, Paul Motian and many more.
A native of Chicago, he brought classical chops into a radicalized improv-jazz setting, with a percussive yet mesmerizing style. His group Revolutionary Ensemble are one of my favorites, a charged unit who's 1976 album The People's Republic somehow found its way to A&M records, but when label head Herb Alpert saw and heard it, he was infuriated! In addition to the aforementioned groups, he was also a major part of the ensembles Driftwood, Computer Minds, Sting and Equal Interest.
Check out the Far-east folk elements he brings to Vietnam, the Revolutionary Ensemble classic for ESP-Disk:
Here's one from The People's Republic: