THERE IS AN EXCEEDINGLY USEFUL VOLUME entitled The Science Fiction Encyclopedia edited by Peter Nicholls (Doubleday, 1979) to which I frequently refer. Recently, as I leafed through its pages en route to looking up something, I came across the following passage:

"The intellectual level of a book is not necessarily expressed by a marketing label. Much adult sf, the works of...Isaac Asimov, for example, is of great appeal to older children, and is to some extent directed at them."

The line of three dots in the above quotation signals the omission of a few words in which the writer specifies two other science fiction writers. I omit them because they may resent the original statement and may not feel I ought to give the remark further circulation.

As for me, I don't object to the comment because, for one thing, I consider it true. I write my

"adult" novels for adults, but I have no objection whatsoever to young people reading them, and I try to write in such a way that my novels are accessible to them.

Why?

First, it is the way I like to write. I like to have the ideas in my novels sufficiently interesting and subtle to catch at the attention and thinking of intelligent adults, and, at the same time, to have the writing clear enough so as to raise no difficulties for the intelligent youngster. To manage the combination I consider a challenge, and I like challenges.

Second, it is good business. Attract an adult and you may well have someone who is here today and gone tomorrow. Attract a youngster and you have a faithful reader for life.

Mind you, I don't write as I do with the second reason in mind; I write as I do for the first reason I gave you. Nevertheless, I have discovered that the second reason exists, and I have long lost count of the number of people who tell me they have an astronomical number of my books and that they "were at once hooked after reading my book, so-and-so, when they were ten years old."

But if the same books can be read by both adults and youngsters, what is the distinction between truly adult books (ones that the writer of the item in The Science Fiction Encyclopedia would judge as possessing a high "intellectual level") and truly juvenile books?

Let's see. Can it be vocabulary? Do adult books have "hard words" while juvenile books have "easy words"?

To some extent, I suppose that might be so. If an author makes a fetish of using unusual words, as William Buckley does (or Clark Ashton Smith, to mention someone in our own line), then the writing grows opaque for youngsters and adults alike, for it is my experience that the average adult does not have a vocabulary much larger, if any, than a bright youngster does.

On the other hand, if an author uses the correct words, hard or easy, then the bright youngster will guess the meaning from the context or look it up in a dictionary. I think the bright youngster enjoys having his mind stretched and welcomes the chance of learning a new word. I don't worry about my vocabulary, for that reason, even when I am writing my science books for grade school youngsters. I may give the pronunciation of scientific terms they are not likely to have encountered before, and I sometimes define them, but I don't avoid them, and after having given pronunciation and definition I use them freely.

Well, then, is it the difference between long sentences and short sentences?

That is true only in this sense: It is more difficult to make a long sentence clear than it is to make a short one clear. If, then, you are a poor writer and want to make sure that youngsters understand you, stick to short sentences. Unfortunately, a long series of short sentences, like a long stretch of writing with no "hard" words, is irritating to anyone intelligent, young or old. A youngster is particularly offended because he thinks (sometimes with justice) that the writer thinks that because the youngster is young, he is therefore stupid. The book is at once discarded. (This is called "writing down," by the way, something I try never to do.)

The trick is to write clearly. If you write clearly enough, a long sentence will hold no terrors. If you hit the proper mix of long and short, and hard and easy, and make everything clear, then, believe me, the youngster will have no trouble. Of course, he has to be an intelligent youngster, but there are a larger percentage of those than of intelligent oldsters, for life hasn't had a chance yet to dull the youngsters' wits.

Is it a matter of subject matter? Do adult novels deal with death and torture and mayhem and sex (natural and unnatural) and all kinds of unpleasantness, while juvenile novels deal with sweetness and niceness?

You know that's not so. Think of the current rash of "horror" films, which fill the screen with blood and murder and torture and are designed to frighten. Youngsters flock to them, and the gorier they are, the more they enjoy them.

Even censors don't seem to mind the mayhem. When there are loud squawks from the righteous who want to kick books out of school libraries, the objections are most often to the use of "dirty" words and to sex. However, I have, in my time, lived half a block from a junior high school and listened to the youngsters going there and coming back. I picked up a lot of colorful obscenity, both sexual and scatological, in that way, for I had forgotten some of what I had learned as a youngster. I think the youngsters themselves would have no objection to books containing gutter language and sexual detail-or fail to understand them, either. That distinction between adult books and juvenile books is not a natural one but is enforced by adult fiat.

(I admit that I use no gutter language or sex in my juvenile books, but then I use no gutter language and very little sex in my adult books.)

How about action, then? Adult books can pause for sensitive description of all kinds, or for a skillful and painstaking dissection of motivation, and so on. Juvenile books tend to deal entirely with action. Is that right?

Actually, the distinction is not between adults and juveniles, but between a few people (both adult and juvenile) and most people (both adult and juvenile). Most people, of whatever age, are impatient with anything but action. Watch the popular adventure programs on television, subtract the action, and find out what you have left, and then remember that it is adults, for the most part, who are watching them.

On the other hand, my books contain very little "action" (hence no movie sales) and deal largely with the interplay of ideas in rather cerebral dialog (as many critics point out, sometimes with irritation) and yet, says the Encyclopedia, I appeal to youngsters. Clarity, not action, is the key.

Can it be a question of style? Are adult books written in a complicated and experimental style, while juvenile books are not?

To be sure, a juvenile book written in a complicated and experimental style is more apt to be a commercial failure than one written in a straightforward style. On the other hand, this is also true of adult books. The difference is that tortuous style is frequently admired by critics in adult books, but never in juvenile books. This means that many adults, who are guided by critics, or who merely wish to appear chic, buy opaque and experimental books, and then, possibly, don't read them, aside from any "dirty parts" they might have. Proust's Remembrance of Things Past springs to mind. My dear wife, Janet, is reading it, every word, for the second time but there are moments when I see the perspiration standing out, in great drops, on her forehead.

How about rhetorical tricks? Metaphors, allusions, and all the rest of it, depend upon experience, and youngsters, however bright they are, have not yet had time to gather experience.

For instance, my George and Azazel stories are pure fluff, but they are the most nearly adult stories I write. I use my full vocabulary, together with involved sentence structure, and never hesitate to rely on the reader to fill in what I leave out. I can refer to "the elusive promise of nocturnal Elysium " without any indication of what I mean. I can speak of the Eiffel Tower as a "stupid building still under construction " and depend on the reader to know what the Tower looks like and therefore see why the remark is wrong, but apt. Nevertheless, the stories are meant to be humorous and all the rhetorical devices contribute to that. The young person who misses some of the allusions nevertheless should get much of the humor and enjoy the story anyway.

In short, I maintain there is no hard and fast distinction between "adult" writing and "juvenile" writing. A good book is a good book and can be enjoyed by both adults and youngsters. If my books appeal to both, that is to my credit.