To his grandchildren, the 61-year-old Pasadena homeowner is simply "Papa Joe." To longtime friends, Joe Horn is an "average Joe" who leads a rather quiet, dull life as a retired communications computer manager on the outskirts of Houston. But since being catapulted into a national debate for fatally shooting two men he says were burglarizing the house next door, Horn is called everything from a "hero" to a "murdering vigilante." All the furor forced him into seclusion as news media nationwide clamored for interviews and one anonymous caller even made a death threat against him. But now for the first...