Stone Cold by David Baldacci

Oliver Stone, the leader of the mysterious group that calls itself the Camel Club, is both feared and respected by those who've crossed his path.

Keeping a vigilant watch over our leaders in Washington, D.C., the Camel Club has won over some allies, but it has also earned formidable enemies - including those in power who will do anything to prevent Stone and his friends from uncovering the hidden, secret work of the government.