I am helping to edit a book on flying saucers? Isaac Asimov? Surely, I am a leading and vocal skeptic where flying saucers are concerned!

Have I changed my mind now? Do I believe in the existence of flying saucers?

That depends on what you mean by the question. Do I believe that many people have seen something in the sky that they can't explain?

Absolutely! Of course! You bet! Seeing something one can't explain is very common. Every time I watch a magician perform his act I see something I can't explain.

However, when I see something I can't explain, I assume there is a perfectly normal explanation, one that fits in with the structure of the universe as worked out by modern science. I don't instantly jump to the idea that there is no explanation short of the supernatural or of some far-out near-zero-probability hypothesis.

For that reason, I have no tendency to explain every appearance of a light in the sky by declaring it to be a spaceship manned by extraterrestrial beings.

Nowadays, in an effort to gain respectability, people who accept the wilder hypotheses about flying saucers call them "unidentified flying objects" and abbreviate it UFO. On numerous occasions, I have been asked if I "believe" in UFOs.

My usual answer is, "I assume that by UFO you mean 'unidentified flying objects.' I certainly believe that many people have seen objects in the air or sky that they can't identify, and those are UFOs.

But then, many people can't identify the planet Venus, or a mirage. If you are asking me whether I believe that some mysterious object reported is a spaceship manned by extraterrestrial beings, then I must say I am very skeptical. But that, you see, is an identified flying object, and that's not what you're asking about, is it?"

Mysterious objects have been reported in Earth's skies all through history. Usually they are interpreted according to the preoccupations of the day. In ancient and medieval times and in primitive societies, they would be interpreted as angels, demons, spirits, and so on. In technological societies, they would be interpreted as first balloons, then dirigibles, then airplanes, and then spaceships.

Of course, if they're spaceships now, then they've been spaceships all the time, and some people have indeed interpreted Ezekiel's vision in the Bible, for instance, as the sighting of spaceships manned by extraterrestrials.

The modern surge of flying saucer sightings began on June 24, 1947, when Kenneth Arnold, a salesman, claimed he saw bright disk-shaped objects flying rapidly through the air near Mount Rainier. From the shapes he described, the expression "flying saucers" came into being.

Nothing much might have happened in consequence, for wild reports about all sorts of things reach the news media every day and then fade out. In this case, though, the report attracted the attention of Raymond A. Palmer, who was then the editor of the science fiction magazine Amazing Stories.

Palmer may not himself have been a piece of broken pottery, but he was certainly not averse to building circulation by means of items that appealed to crackpots. He had shown this in his earlier work on something completely wacky that he called "The Great Shaver Mystery."

Now he took up flying saucers and single-handedly promoted them into an international mania. That is one connection (an important one) between flying saucers and science fiction.

Mind you, I have a soft spot in my heart for Ray Palmer. Way back in 1938, he bought the first science fiction story I ever sold, and sent me the very first check I ever earned as a professional writer.

Nevertheless, candor compels me to state that for years after this noble deed of his I never had occasion to believe a word he said.

At the other extreme of the flying saucer spectrum is professor J. Allen Hynek. He is a respectable and learned scientist who has spent decades examining the evidence and who remains firmly convinced that there is something there. He doesn't accept the extraterrestrial spacecraft hypothesis, but he thinks that something mysterious underlies the phenomenon, which, if understood, may revolutionize science.

However, in all the years he's been investigating the phenomenon, he's come up with-nothing! Far from revolutionizing science, his work has not added one even marginal item to the world of physical science.

Then what am I doing helping edit this anthology?

That brings us to the second connection between flying saucers and science fiction. The whole concept of flying saucers-the whole notion of thousands upon thousands of spaceships hovering about us without ever seeming to do anything or to affect us in any way-has supplied science fiction writers with an endless supply of story material.

All of us have written flying saucer stories. I have myself, and one of them is included in this book.

Generally, we have to deal with a situation in which extraterrestrial spacecraft visit us, but keep out of sight for some reason, or decide not to do anything for some reason, or try to do something and fail for some reason, or fail to manage to convince Earthpeople they are real for some reason.

You see, science fiction writers, being sane and rational, have to find some reason for so many spaceships doing nothing. Usually the results turn out to be funny, satiric or ironic; sometimes tragic. Very often, they prove to be stories that are entertaining and good-so what we have done is to collect a sizable number of them into one book for your delectation.

Come, see for yourself that every cloud has a silver lining, and that even the silliest notions can undergo a sea change into something rich and strange in the hands of skilled science fiction writers.