In America's newly declared war on terrorism, the most critical weapon in its military arsenal is not a lethal force of commandos or precision-guided missiles. It is information. The Pentagon's intelligence forces are preparing to fight a war unlike any other. Long accustomed to counting weapons, monitoring troop movements and identifying the enemy's chain of command, the Pentagon's massive intelligence apparatus must now hunt down a shadowy web of terrorists in Afghanistan who keep moving to new hiding places in caves and tunnels.