"THE THIRD ILLUSION," said a soft voice. And he was holding a billowing net and a strange three-pronged weapon. The sound of a roaring multitude reached his ears. He blinked, orientating himself to the new illusion, and saw that he was in an immense stadium. Curiously-garbed people were staring down at him. _My God_, he thought. _The Coliseum!_ And even as the thought of recognition burst upon him, he saw his opponent advancing over the bloody sand. It was a swarthy, broad-shouldered man in a leather tunic, wielding a thick, short sword. Swordsman against netman. It was deadly, deadly. Hendriks knew enough history to be aware of what was expected of him. He had to ensnare the swordsman in the net and kill him with the trident before that fierce sword could pierce his heart. It was anything but an equal contest, but with proper agility-- The sword flashed on high. Desperately Hendriks parried it with the hilt of his trident and whirled the net through the air. The swordsman laughed and leaped back. Hendriks advanced, looking for an opening. The roars of the crowd were deafening. He swung the net tentatively, readying himself for the cast. Tired muscles throbbed in his arms and thighs. The swordsman retreated deftly, smiling. He looked confident. Hendriks began the cast. Suddenly the sword flashed again. It was a lightning-fast attack. Hendriks managed to get the trident up to protect himself; the impact sent pain coursing up his arm, and, numbed, he dropped the three-pronged weapon. Laughing jovially, his opponent kicked the trident far across the stadium and advanced with the sword. Hendriks knew what he had to do. He dropped to his knees before the advancing swordsman and gestured toward the audience. The swordsman nodded. He lifted the sword, held it over Hendriks' head, and looked up at the grand dais. Hendriks looked up as well. The thumbs were down. Emphatically so. The sword began to descend-- * * * * * "THE FOURTH ILLUSION," said the voice. He was racing madly down the Indianapolis Speedway, bobbing along at nearly 150 miles an hour in a flimsy-looking little racing auto. Blurs whizzed by on all sides. Ahead of him he saw a car suddenly swerve into the embankment and burst into a mass of flames. With desperate urgency he yanked on the wheel, tried to avoid the pileup-- And failed. He felt his car going end over end into the air, and shut his eyes, waiting for the explosion that would follow. "THE FIFTH ILLUSION," the voice said. He was in a prehistoric jungle; strange stumpy trees were all around, lush vegetation. A slow-moving beast of immense size was thundering away from him, its tiny head close to the ground snapping up vegetation without cease. Overhead a leather-winged flying reptile moved through the air in jerky swoops. There was sudden thunder behind him. He turned.