All mail was sent first to the office of the Executive Secretary, Mr. Brian Taggert. Most of it—somewhat better than ninety-nine per cent—went directly on to Mr. Balfour's desk, if it was so addressed; Brian Taggert would never have been so cruel as to deprive Mr. Balfour of the joy of sorting through the thousands of crackpot letters in search of those who had the true spark of mysticism which so fascinated Mr. Balfour.

Mr. Balfour was a crackpot, and it was his job to take care of other crackpots—a job he enjoyed immensely and wholeheartedly, feeling, as he did, that that sort of thing was the only reason for the Society's existence. Of course, Mr. Balfour never considered himself or the others in the least bit crackpottish, in which he was just as much in error as he was in his assumption of the Society's raison d'être.

Ninety per cent of the members of the Society for Mystical and Metaphysical Research were just what you would expect them to be. Anyone who was "truly interested in the investigation of the supranormal", as the ads in certain magazines put it, could pay five dollars a year for membership, which, among other things, entitled him to the Society's monthly magazine, The Metaphysicist, a well-printed, conservative-looking publication which contained articles on everything from the latest flying saucer report to careful mathematical evaluations of the statistical methods of the Rhine Foundation. Within its broad field, the magazine was quite catholic in its editorial policy.

These members constituted a very effective screen for the real work of the society, work carried on by the "core" members, most of whom weren't even listed on the membership rolls. And yet, it was this group of men and women who made the Society's title true.

Mr. Brian Taggert was a long way from being a crackpot. The big, dark-haired, dark-eyed, hawknosed man sat at his desk in his office on the fifth floor of the Society's building and checked over the mail. Normally, his big wrestler's body was to be found quietly relaxed on the couch that stood against a nearby wall. Not that he was in any way averse to action; he simply saw no virtue in purposeless action. Nor did he believe in the dictum of Miles Standish; if he wanted a thing done, he sent the man most qualified to do it, whether that was himself or someone else.

When he came to the letter from Coney Island, New York, he read it quickly and then jabbed at a button on the intercom switchboard in his desktop. He said three syllables which would have been meaningless to anyone except the few who understood that sort of verbal shorthand, released the button, and closed his eyes, putting himself in telepathic contact with certain of the Society's agents in New York.

Across the river, in the Senate Office Building, a telephone rang in the office of Senator Mikhail Kerotski, head of the Senate Committee on Space Exploration. It was an unlisted, visionless phone, and the number was known only to a very few important officials in the United States Government, so the senator didn't bother to identify himself; he simply said: "Hello." He listened for a moment, said, "O.K., fine," in a quiet voice, and cut the connection.

He sat behind his desk for a few minutes longer, a bearlike man with a round, pale face and eyes circled with dark rings and heavy pouches, all of which had the effect of making him look like a rather sleepy specimen of the giant panda. He finished the few papers he had been working on, stacked them together, rose, and went into the outer office, where he told his staff that he was going out for a short walk.

By the time he arrived at the brownstone building in Arlington and was pushing open the door of Brian Taggert's office, Taggert had received reports from New York and had started other chains of action. As soon as Senator Kerotski came in, Taggert pushed the letter across the desk toward him. "Check that."

Kerotski read the letter, and a look of relief came over his round face. "Not the same typewriter or paper, but this is him, all right. What more do we know?"

"Plenty. Hold on, and I'll give you a complete rundown." He picked up the telephone and began speaking in a low voice. It was an ordinary-sounding conversation; even if the wire had been tapped, no one who was not a "core" member of the S.M.M.R. would have known that the conversation was about anything but an esoteric article to be printed in The Metaphysicist—something about dowsing rods.

The core membership had one thing in common: understanding.

Consider plutonium. Imagine someone dropping milligram-sized pellets of the metal into an ordinary Florence flask. (In an inert atmosphere, of course; there is no point in ruining a good analogy with side reactions.) More than two and a half million of those little pellets could be dropped into the flask without the operator having anything more to worry about than if he were dropping grains of lead or gold into the container. But after the five millionth, dropping them in by hand would only be done by the ignorant, the stupid, or the indestructible. A qualitative change takes place.

So with understanding. As a human mind increases its ability to understand another human mind, it eventually reaches a critical point, and the mind itself changes. And, at that point, the Greek letter psi ceases to be a symbol for the unknown.

When understanding has passed the critical point, conversation as it is carried on by most human beings becomes unnecessarily redundant. Even in ordinary conversation, a single gesture—a shrug of the shoulders, a snap of the fingers, or a nose pinched between thumb and forefinger—can express an idea that would take many words and much more time. A single word—"slob," "nazi," "saint"—can be more descriptive than the dozens of words required to define it. All that is required is that the meanings of the symbols be understood.

The ability to manipulate symbols is the most powerful tool of the human mind; a mind which can manipulate them effectively is, in every sense of the word, truly human.

Even without telepathy, it was possible for two S.M.M.R. agents to carry on a conversation above and around ordinary chit-chat. It took longer, naturally; when speaking without the chit-chat, it was possible to convey in seconds information that would have taken several minutes to get over in ordinary conversation.

Senator Kerotski only listened to a small part of the phone discussion. He knew most of the story.

In the past eight months, six anonymous letters had been received by various companies. As Taggert had once put it, in quotes, "We seem to have an Abudah chest containing a patent Hag who comes out and prophesies disasters, with spring complete."

The Big Bend Power Reactor, near Marfa, Texas, had been warned that their stellarator would blow. The letter was dismissed as "crackpot," and no precautions were taken. The explosion killed nine men and cut off the power in the area for three hours, causing other accidents due to lack of power.

The merchant submarine Bandar-log, plying her way between Ceylon and Japan, had ignored the warning sent to her owners and had never been heard from again.

In the Republic of Yemen, an oil refinery caught fire and destroyed millions of dollars worth of property in spite of the anonymous letter that had foretold the disaster.

The Prince Charles Dam in Central Africa had broken and thousands had drowned because those in charge had relegated a warning letter to the cylindrical file.

A mine cave-in in Canada had extinguished three lives because a similar letter had been ignored.

By the time the fifth letter had been received, the S.M.M.R. had received the information and had begun its investigation. As an ex officio organ of the United States Government, it had ways and means of getting hold of the originals of the letters which had been received by the responsible persons