As a board member of Frack Free Denton, Adam Briggle helped coordinate the effort to ban fracking in the city. Local bans on the practice were ultimately disallowed by the Texas Legislature. This hour, we’ll talk to Briggle, an assistant professor at UNT, about his experience in grass-roots politics, which he writes about in “A Field Philosopher’s Guide to Fracking: How One Texas Town Stood Up to Big Oil and Gas” (Liveright).