"I am only remarkable because I can't help it," says editor Judy-Lynn del Rey. She is not being immodest (though modesty is not and should not be one of her most notable qualities); she is quoting the Sawhorse in one of the seven Oz books she has just published for the first time in mass-market paperback.

"I always keep my promises, no matter how foolish they are." This time she is quoting the Nome King (spelled without a "G" because author L. Frank Baum thought its pronunciation would be less confusing for young readers), but she is also remembering a promise that she and her husband, science fiction writer and editor Lester del Rey, have been making to each other for years.

"The Oz books have been favorites of Lester's and mine for years," she says. "We grew up on them, and the books kept growing as we did -- they are great children's books, but much more than children's books. We have thought about publishing them and talked about it for years, but a mass market for fantasy did not exist.

"Now that we have created the fantasy mass market and have an imprint with our name on it, we decided, why shouldn't we do what we want to?"

And so it came to pass that the bookstores now have seven volumes of the Oz series in a mass market paperback edition issued by Ballantine books under its Del Rey imprint. The first titles, selling at $1.95 apiece, are: "The Wizard of Oz," "The Land of Oz," "Ozma of Oz," "Dorothy and the Wizard in Oz," "The Road to Oz," "The Emerald City of Oz" and "The Patchwork Girl of Oz." Seven more will be published next year.

The road to a paperback mass market has been considerably longer than the yellow brick one that is a notable landmark of Oz. Begun around the turn of the century, the Oz books written by Baum have been more or less premanently available in hardcover editions and relatively expensive trade paperbooks, but the new Ballantine edition represents a significant escalation of the market. Traditionally, booksellers have tended to keep the Oz books in the special ghetto area reserved for children's reading. Ballantine is promoting the books as adult reading and publishing them in a format that will allow display in the familiary paperback racks found in drugstores, supermarkets and airports.

When Del Rey casually mentions that "we have created the fantasy mass market," she is hardly exaggerating, whether the "we" refers to Ballatine (which published the first authorized American paperback edition of the Tolkien novels) or to its Del Rey subdivision, which has rapidly developed new talents in fantasy and science fiction during the last few years.

Among the notable Del Rey successes in the field of adult fantasy, probably the most spectacular is "The Chronicles of Thomas Covenant," which became an instant classic when its first three volumes were published two years ago. A second trilogy will appear in June, and eventually it will become what Del Rey calls "a tetralogy of trilogies. Evidently, it is Ballantine's hope that the large readership turned on to fantasy by such publications may be ready to devour the Oz books -- in many cases, for the second time around.

Curiously, considering their status as adult reading (which has long been established in a limited circle and is now being pushed by Ballatine), the Oz books owe a lot of their interest to the feedback from young readers that Baum incorporated into the series.

"I have used many suggestions conveyed to me in letters from children," he wrote in 1910 in the introduction to "The Emerald City of Oz." " . . . I am merely an editor or private secretary for a host of youngsters whose ideas I am requested to weave into the thread of my stories."

Rather than such arbitrary pigeonholes as "juvenile" or "adult," the Oz books probably belong (with "The Odyssey," "Robinson Crusoe" and a few other titles) in a universal category that transcends age barriers.

"We're trying to awaken the Oz-consciousness of the world," says Judy-Lynn Del Rey, "to put Oz on the fantasy map and make it real to people the way Tolkien's Middle Earth or C. S. Lewis' Narnia are. Everybody knows 'The Wizard of Oz,' of course -- but that's only the beginning, and 'The Wizard' is not necessarily the best book in the series."

What does she think are the prospects for this venture? In answer, she quotes the Shaggy Man, one of the distinguished American immigrants who have been given permanent residence in the magic kingdom:

"I've learned from long experience that every road leads somewhere."