A Practice Note discussing how the Railroad Commission of Texas (RRC) regulates oil and gas drilling, exploration, and production. This Note addresses drilling permits, well spacing (Rule 37), well density (Rule 38), horizontal wells (Rule 86), special field rules, Unconventional Fracture Treated (UFT) fields, allocation and production sharing agreement (PSA) wells, spacing and density exceptions, production allowables, and proration units. It also provides guidance for permitting horizontal wells in unconventional reservoirs.