Patrick Seamus O'Hara spent 25 years as a dedicated Protestant. He was so convinced that all Catholics are eternally damned that he would go to the parking lots of local Catholic parishes during Mass and leave tracts on the windshields of the cars, urging them to repent of their Catholic faith. In 1998, he met an equally dedicated group of cradle and convert Catholics online. Over the next two years, he debated with them, challenging their beliefs. In 2001, convinced by their knowledge of scripture, the writings of the Early Fathers, and their consistent witness to him, he entered the Catholic...