"Bust!" With that crack of an undercover agent's voice on the Harris County sheriff's radio, an unmarked white Chrysler rips out of a gravel driveway. From other directions, four cars race down a seedy strip of highway toward an abandoned gray house. A vice raid is under way on Houston's north side, and alongside the sergeant in the Chrysler's front seat, citizen Dan Hurlbut, smut buster, unsheathes a dark cigar and relishes the upcoming catch.
In a city known for world-class pornography, Hurlbut has carved a swath of reform. An executive-search consultant in his more mundane life, the burly 59- year-old...