stone-age culture lingering in an out-of-the-way place. Changing tribes was easy, for all tribes belonged to Man, but renouncing machinery for jungle tools would be more difficult. A man could change his politics, his friends, his religion, his country, but Man's tools were a part of his body. Having used a high-powered rifle, the man subsumed the weapon, made it a part of himself. Trading it for a stone axe would be like cutting off his arm. Man was a user of tools, a shaper of environments.

That was it, he thought. The reason for his sudden rebellion, the narrow dividing line between tolerable and insufferable wars. A war that killed human beings might be tolerable, if it left most of civilizations' industry intact, or at least restorable, for although men might die, Man lived on, still possessing his precious tools, still capable of producing greater ones. But a war that wrecked industry, left it a tangled jumble of radioactive concrete and steel—that kind of war was insufferable, as this one threatened to be.

The idea shocked him. Kill a few men, and you scratch the hide of Historical Man. But wreck the industry, drive men out of the cities, leave the factories hissing with beta and gamma radiation, and you amputate the hands of Historical Man the Builder. The machinery of civilization was a living body, with organismic Man as its brain. And the brain had not yet learned to use the body for a constructive purpose. It lacked coordination, and the ability to reason its actions analytically.

Was he basing action on analytic reason?

Another hour had passed. And then he heard it. The sound of faint sonar communication. Quickly he nosed upward to twenty feet, throttled back to half speed, and raised the periscope. With his face pressed against the eyepiece, he scanned the moonlit ocean in a slow circle. No lights, no silhouettes against the reflections on the waves.

He started the pumps and prepared to surface. Then the conning tower was snorting through the water like a rolling porpoise. He shut off the engines, leaving the sub in utter silence except for the soft wash of the sea. He adjusted the sonar pickups, turned the amplifier to maximum, and listened intently. Nothing. Had he imagined it?

He jabbed a button, and a motor purred, rolling out the retractable radar antenna. Carefully he scanned the sky and sea, watching the green-mottled screen for blips. Nothing—no ships or aircraft visible. But he was certain: for a moment he had heard the twitter of undersea communicators.

He sat waiting and listening. Perhaps they had heard his engines, although his own equipment had caught none of their drive-noise.

The computer was able to supervise several tasks at once, and he set it to continue sweeping the horizon with the radar, to listen for sonar code and engine purr while he attended to other matters. He readied two torpedoes and raised a rocket into position for launching. He opened the hatch and climbed to stand in the conning tower again, peering grimly around the horizon.

Minutes later, a buzzer sounded beneath him. The computer had something now. He glanced at the parabolic radar antenna, rearing its head a dozen feet above him. It had stopped its aimless scanning and was quivering steadily on the southeast horizon. Southeast?

He lowered himself quickly into the ship and stared at the luminous screen. Blips—three blips—barely visible. While he watched, a fourth appeared.

He clamped on his headsets. There it was! The faint engine-noise of ships. His trained senses told him they were subs. Subs out of the southeast? He had expected interception from the west—first aircraft, then light surface vessels.

There was but one possible answer: the enemy.

He dived for the radio and waited impatiently for the tubes to warm again. He found himself shouting into the mic.

"Commsubron Killer, this is Sugar William Niner Zero. Urgent message. Over."

He was a long way from the