Karl Keating is the founder and president of Catholic Answers.
He had been working as an attorney for several years when, on leaving Mass one Sunday, he found anti-Catholic tracts on the windshields of the cars in the church parking lot. He wrote his own tract in reply and distributed copies of it at the Fundamentalist church responsible for the anti-Catholic tract. That was the start of what has become the country’s largest lay-run apologetics and evangelization organization.
Catholic Answers was incorporated in 1982, and in 1988 Karl left the practice of law and went into apostolic work full time. That year marked the publication of his Catholicism and Fundamentalism, the first book to deal extensively with challenges posed by "Bible Christians." Other books followed: What Catholics Really Believe, Nothing But the Truth, The Usual Suspects, and Controversies. He is at work on several more titles.
Frankly, I've heard better debates. He doesn't do a bad job, but there are others who present the Catholic case with more strength in a debate. Unfortunately, most of the MP3 copies of those debates cost money...I'll try to track down some free versions.
The Debates:
Karl Keating vs. Peter Ruckman 1987 MP3
Karl Keating vs. Bart Brewer 1987 MP3 (poor recording quality)
Karl Keating vs. Dave Hunt on Action Sixties February 1993 MP3
*Via PhilVaz
The Ruckman debate is on You Tube, also a debate vs the Iglesia Ni Kristo (Church of Christ).