If Miles Davis had stopped making music in the 1950s, he would be remembered as one of the most eloquent and influential trumpeters in jazz. But Davis, an Alton native who grew up in East St. Louis, was also a visionary who wasn’t afraid to shake things up and didn’t believe in looking back. Beginning in the late 1960s, that meant venturing beyond acoustic post-bop jazz to explore the improvisational possibilities of rock.