Jascha Heifetz (; February 2 [O.S. January 20] 1901 – December 10, 1987) was a Lithuanian-American violinist. He is widely regarded as one of the greatest violinists of all time. Born in Vilnius, he moved to the United States as a teenager, where his Carnegie Hall debut was rapturously received. He was a virtuoso from childhood. Fritz Kreisler, another leading violinist of the twentieth century, said after hearing Heifetz's debut, "We might as well take our fiddles and break them across our knees." He had a long and successful performing career; however, after an injury to his right (bowing) arm, he switched his focus to teaching.

Late in life, Heifetz was known as a dedicated teacher and a champion of socio-political causes. He publicly advocated to establish 9-1-1 as an emergency phone number, and crusaded for clean air. He and his students at the University of Southern California protested smog by wearing gas masks, and in 1967, he converted his Renault passenger car into an electric vehicle.