Bay Area MCs have long been a fixture of the national stage — think Too Short, MC Hammer, Hieroglyphics, renowned slanguist E-40 — but they were just the prominent tip of an iceberg that reached impossibly deep. In this long and winding history, Mosi Reeves traces the region’s evolution, recruiting tour guides and archival clips to take you back to the old school in style.

Yet the third moment that catalyzed Bay Area hip-hop wasn’t a singular record like Timex Social Club’s “Rumors,” or an artist like Hammer and Short. It was the sound of walloping, all-enveloping bass.

Made for surgically enhanced car and jeep stereos, the bass colossus is as much a feature of hip-hop in the mid-’80s as the pounding Roland TR-808 machine, from Rick Rubin’s production on LL Cool J’s “Rock the Bells” and T La Rock’s “It’s Yours” to Rodney O and DJ Joe Cooley’s “Everlasting Bass” and Dr. Dre’s work on Eazy-E’s “The Boyz-N-The Hood.” It also mirrors the crack-cocaine epidemic that began to blight and distort communities across the country. As street life turned treacherous, the specter of the hustler, and whether to become one, cast a growing shadow.