The line went dead. Blade put the receiver back in place and lay back in the bed. Like his identity, his profession was concealed while he was abroad behind a cover story and a code. But there were reasons for concealing his profession that went beyond his personal safety.

There was no single word to describe Blade's profession, a profession unknown to the public-or so he and J both devoutly hoped. And Blade doubted if there ever would be a word. How can you describe a man whose job it is to travel into alternate dimensions-not quite on alternate Thursdays, but much the same way a deep-sea sailor goes on a long voyage? Blade didn't know. All he knew was that he was the best man in the world today for that job. And he enjoyed it. He had an adventurous temperament, but he had managed to be born in a century when there were few professions that offered that much chance for adventurers. He knew that he was very lucky.

His luck had begun the day that England's most brilliant and eccentric scientist, Lord Leighton, had decided to make an experiment. The experiment consisted of linking a man's brain directly into an advanced computer-or at least what had been an advanced computer then. Compared to what Lord Leighton used now, that first computer was hardly more than a child's toy. Leighton's goal was to radically increase the powers of both the human and the electronic intelligences, each taking strength from the other.

A good idea. Blade rather hoped that one day the original experiment could be carried out successfully. But things had not turned out as the scientist planned. Blade had awakened in a strange, barbaric world in which savage tribes and the votaries of even more savage religions roamed about and warred on one another. Thanks to his training, his muscles, his quick reflexes, and his quicker wits, he had survived and somehow been snatched back to Lord Leighton's laboratory.

Immediately Lord Leighton's original project went aglimmering for here was something ten times as important. The existence of alternate dimensions-Dimension X-had frequently been theorized. Now it had been proved. And now it seemed possible to travel at will into those dimensions, explore them, discover their resources of knowledge and raw materials, bring wealth back to England. It was a discovery of enormous national importance.