As he rounded the horseshoe and saw the sign from another angle, he realized that there was no building there. Then he concluded that it must be a plane. But it suddenly shot off to the southwest, rising into the overcast with blinding speed.

What happened to this man? What did he see? It would be easy to dismiss his experiences as a pair of hallucinations. Easy to debunk this one.

There is, however, a problem. The problem is the man himself, and his extraordinarily apt qualifications. He is a leading perceptual psychologist with encyclopedic knowledge of just exactly how the brain perceives things, and what misperceptions mean. What's more, he has a near-photographic memory and eyes so superb that he can see the moons of Jupiter unaided.

He is also highly intelligent and exceptionally emotionally stable, having had many hundreds of hours of psychoanalysis as part of his clinical training.

Anybody can have a hallucination or a misperception. But this highly qualified man feels certain that what he saw was actually there. Interestingly, other drivers did not react to it at all. I wonder if that might not be because they believed an illusion that this man's mind was too highly trained to mistake. Most people saw a plane and, an advertising sign. But this acute, trained mind saw beyond the camouflage to what was really there — a device of unknown origin and purpose.

How interesting that such an outrageous perceptual joke would be played on a skilled perceptual scientist — who himself has superb perceptual equipment. Or perhaps the visitors were indifferent, and chance played the joke. Then again, maybe it wasn't a joke at all. What about the light shining in his eyes — did they use it to learn something from him, or induce him to act in some drama of importance to their enigmatic designs?

I would not be at all surprised if the visitors are real and are slowly coming into contact with us according to an agenda of their own devising, which proceeds as human understanding increases. If they are not from our universe it could be necessary for us to understand them before they can emerge into our reality. In our universe, their reality may depend on our belief. Thus the corridor into our world could in a very true sense be through our own minds.

The idea of parallel universes is neither proven nor new. It has a distinguished history in physics. Of course, the conditions under which movement between universes might be possible are not known.

We have seen that the visitors are not fairies, and that their ships are not figments of the wind. Now that we know this, what more will we learn?

Humanity could be clutching the frail barque of an outmoded world view while the wind of the mind is swaying the stars into very real craft, and out of them is coming... a faint call for help from a lady in a flowered dress.