Tim Russert is best known for his aggressive questioning that helped turn "Meet the Press" into the most widely watched Sunday morning interview show in the nation.

Russert died today of an apparent heart attack at his office in Washington, at the age of 58.

He took the helm of "Meet the Press" in December of 1991. He brought with him a Jesuit education, a law degree, and experience as an aide to the late Democratic Senator Daniel Patrick Moynihan of New York.

The native of Buffalo, New York, became known for a relentless style of questioning that made some politicians reluctant to appear. But they were confident that they could claim extra credibility if they survived his grilling intact.

NBC colleague Tom Brokaw, speaking about Russert's passion for politics, says Russert's death came during a political campaign that "he loved."

Washingtonian magazine once dubbed him the best journalist in town, and described "Meet the Press" as "the most interesting and important hour on television." This year, Time magazine named him one of the 100 most influential people in the world.

Russert also wrote the best-selling books "Big Russ and Me," in 2004, and "Wisdom of our Fathers," in 2006.

Russert was married to Maureen Orth, a writer for Vanity Fair. They had one son, Luke.