Those people will be contacted in a few days and will have a week to decide whether or not to participate. Now-questions?"

Petrie's hand went up with the others. Draut chose someone else. "Mr. Draut, how can such a thing as real invisibility be possible? I thought it'd been proven impossible?"

"So did I," Draut agreed gravely, drawing a chuckle from the crowd. "As explained to me, it's somewhat akin to the way a phased force beam can carry energy and force through solid objects without affecting them, only delivering its energy when it intersects another properly phased beam. The beams are still there the rest of the time, but they simply don't interact with matter. I suspect something similar is being done with the light which would normally have reflected from the Angel, sending it right through him or something. That's the reason for the neckband, by the way. I'm told it's very hard to see when you're invisible because of what's being done with that light. Relaying the images from the neckband sensors to the appropriate Angel will help to alleviate this problem. I'm afraid that's the best explanation I can give; anything further would have to be in mathematics, which I don't speak. Next question? Yes, you."

"I realize there's a lot of danger in the world these days, but do you think there's a market for invisible bodyguards? Will the public accept something that radical?"

"If not, I've just lost a lot of money, Draut replied with a slight smile. "Obviously, I think the market is there. Yes. You in the middle."

Petrie chose his words carefully. "It seems to me, Mr. Draut, that workable invisibility opens a large box of snakes with regards to such activities as espionage, terrorism, and crime, to name just three. What are you doing to safeguard this discovery against possible misuse?"

"I'm sure you'll understand that I can't discuss our security arrangements with you." Draut's face was suddenly expressionless. "But I assure you there is no way for the invisibility secret to slip out. Very few people know the details, and even their names are highly classified information."

"Then what are you doing to make sure your own people don't abuse their knowledge?" Petrie persisted.

"All I can say is that there is no danger of that," Draut said. "Period; end of file. Next question?"

Draut answered a few more questions, but Petrie wasn't really listening. He'd spent years watching people's faces, and there was something in Draut's expression he didn't like. Studying the lined, middle-aged face, he tried to figure out what it was. Humor? Mockery? Whatever it was, Petrie had a solid gut-level sense that there was more to this project than met the eye. Draut hadn't seemed very happy with his question about security. Did he have some industrial espionage applications in mind?

Draut answered a few more questions, but Petrie wasn't really listening. He'd spent years watching people's faces, and there was something in Draut's expression he didn't like. Studying the lined, middle-aged face, he tried to figure out what it was. Humor? Mockery? Whatever it was, Petrie had a solid gut-level sense that there was more to this project than met the eye. Draut hadn't seemed very happy with his question about security. Did he have some industrial espionage applications in mind?

The news conference ended a few minutes later, and the reporters scrambled from the room, looking for quiet corners from which they could call in the story. Petrie lingered, hoping for another look at Draut's face, but the older man left immediately, presumably returning to his office. For a moment Petrie was tempted to follow, to try and badger a few more answers out of him. But Security would probably run a slalom course down his back if he tried it. Besides, confrontations were more fun when both sides had a few facts on hand.

Turning, Petrie strode from the room. The first step, obviously, was to dig up his share of those facts.

Mrs. Irma Lieberman had just settled into her favorite easy chair-the one by the window-and had begun her afternoon's knitting when a knock rattled her door. She looked up, gnarled face wrinkling with surprise and more than a touch of apprehension. Only Mrs. Finch next door visited her these days, and Mrs. Lieberman could always hear her door open and close before she came over. Were the gangs of pre-teenage children becoming bold enough to come right into the senior citizen housing complexes? The thought made her shiver.

The knock came again. "Who's there?" she called.

"Mrs. Lieberman? a strange voice said. "I'm Alex Horne of Draut Enterprises. I'd like to talk to you about a new service we're starting."

Whatever it was, she knew she couldn't afford it. But it might be nice to talk to someone for a while, even if it meant enduring a sales pitch. Carefully standing up, she walked to the door and warily cracked it open.

The man standing there certainly looked like he belonged to Draut Enterprises. Young, neat, clean, and dressed in a suit that had probably cost half her yearly stipend, he was all smiles as he held out an ID

card for her perusal. She hesitated only a moment, then closed the door, removed the chains, and opened it wide. Still smiling, he stepped into her apartment.

"Mrs. Lieberman," he said when they were seated, "my company is beginning a new type of bodyguard service called Guardian Angels. Have you heard of it?"

Was the Pope a Catholic? Facts, speculations, and rumors about Guardian Angels had dominated the news for days now. "That's the one with invisible people, isn't it?"

"Right," he nodded. "As part of our test program, we would like you to accept one of our Angels, free of charge, for the duration of the study."

For a moment she just stared at him, so unexpected was his offer. "Why, I... well, that's very generous of you, young man... uh, I..."

Horne came to her rescue. "You don't have to make a decision today," he said, pulling a colorful brochure from an inside pocket. "Here's some more information about Guardian Angels. Please read it and give us your answer by next Tuesday. There's a number in the brochure for you to call; just give the person your name and we'll set up an appointment for you. Do you have any questions?

Horne came to her rescue. "You don't have to make a decision today," he said, pulling a colorful brochure from an inside pocket. "Here's some more information about Guardian Angels. Please read it and give us your answer by next Tuesday. There's a number in the brochure for you to call; just give the person your name and we'll set up an appointment for you. Do you have any questions?

"Please do. And I would really encourage you to accept an Angel, Mrs. Lieberman. I think it would be rewarding for you, as well as helpful for us. Well, I have many other calls to make this afternoon, so I'd better be going. Thank you for your time."

He left. Alone again, door securely locked and chained behind her, Mrs. Lieberman sat back down and carefully read the brochure. The idea that someone would actually offer such a thing to her took some getting used to, and she had to continually remind herself this was really happening. Still... there were some disturbing aspects to this whole thing. Having someone dogging your every step was strange enough, but for it to be someone you couldn't even see was downright spooky. Would the bodyguard want to come into her apartment with her? And if she refused permission would he do so anyway? She could see no way of stopping him.

Closing the brochure with more force than necessary, she stood up and began to pace-a slower and more cautious motion than in her youth, but still an effective way to drain off nervous energy. She kept at it for quite a while, but her conflicting thoughts refused to sort themselves out. Pros and cons, wishes, fears, and questions came and went, adding to her confusion instead of dispelling it.