Warren is a Toronto-based lawyer, author and consultant. Born in Montreal, Warren has lived in virtually every part of Canada, and in the United States. He and his wife have four children.

Warren has written three bestselling books: one on international terrorism, Unholy Alliances (Lester, 1992); a national bestseller about organized racism, Web of Hate (HarperCollins, 1994, and republished in 1996 and 2001).

Warren has also been a newspaper and magazine columnist.

Kicking Ass in Canadian Politics (Random House, 2001).
A best-selling novel, and, most recently, a book about political communications.