It’s 10 a.m. on the last Saturday in February and local activist Adisa Banjoko is on one hell of a book tour. Inspired by renowned area rap vets hawking their albums out of car trunks, Banjoko sells his Lyrical Swords series — a collection of essays, interviews, and political ideas related to hip-hop, martial arts, and even chess — mostly hand-to-hand on the streets. For the release of his latest effort, Lyrical Swords Volume II: Westside Rebellion, though, he’s forgoing the pavement to visit a place few big-name authors tend to tread — the California prison system. After speaking with Muslim inmates in Vacaville earlier in the month, today the San Jose resident is working the exercise yard at San Quentin. His goal: to educate the public about the importance of black and Latino unity, an issue especially important in light of tumultuous race tensions behind bars in this state.