Up the aisle at the drugstore, between the Cheez Balls and the gift wrap, there's a million-dollar gamble on the nation's latest literary hybrid.

Right there at the end of the row, snugged up against the Puffs and racked flat like Golden Oldies amid the flea collars and panty hose, is the duck-billed platypus of American publishing. It reads like a novel, looks like a magazine, and calls itself Mag-A-Book, the self-proclaimed "best new idea in reading since books!"

But then, they are books. Four of them, the size and heft of Newsweek, done up on glossy stock, lavishly splattered with national advertising, beckoning from their own display risers at $1.95: Louis L'Amour's "Westward the Tide"; Sylvia Wallace's "Empress" ("a woman on a dangerous pinnacle of love and power"); Lois Wyse's family saga "Far From Innocence"; and "Kiss Daddy Goodbye," a horror novel by Thomas Altman.

If the titles are familiar, it's because each already has been a Bantam mass-market paperback, making Mag-A-Book a reprint of a reprint. With as many as 160 pages each--including the one-page "author profile"--and a picture of the original paperback on the front, "We're reprinting the book in its total form: cover, guts, everything," says Mag-A-Book's creator, Benjamin Sher.

A few days ago the first salvo of Mag-A-Books hit 30,000 supermarkets, drugstores and other outlets, riding on the cover-line promise that it's "Better than a paperback: easier to read, easier to carry, easier price."

"We're going to stimulate reading again," says Sher, chairman of Sabco Communications Inc., the publisher of Mag-A-Book. With a one-time printing of 200,000 for each title, "it's the new paperback revolution." By offering proven bestsellers to an unconventional market, he hopes to "recreate the essence of the mass-market book's historical appeal--good reading at a reasonable price."

Traditional vendors have mixed reviews of the venture. The mighty Waldenbooks chain will carry Mag-A-Books; rival giant B. Dalton will not. "We feel that it's basically competing with the same books we have in the store," says B. Dalton executive Marcia Wattson, since browsers are not after a specific format but "just looking for something to read." She says that "it's a good idea for K marts or drugstores, but B. Dalton does not want to portray that as their image." Robert Haft, head of the burgeoning Crown Books chain, says, "We feel they're not as high a quality as a real book. At our prices, for the same money you can get a real book, not an imitation book."

But Sher believes that a market is there. He conceived the idea some three years ago, after "seeing what's happened to the book business." Soft-cover publishers literally used to bank on readers walking into a store to buy one book and picking up two or three more on impulse. But with prices up, often to $3.95, impulse sales down and paperback returns approaching one-third of all titles shipped, Sher felt "the timing was absolutely perfect" for a new format by which "I could create that multiple sale" by pricing the product under $2.

He decided on a target audience that is 75 percent women, aged 18 to 49. "She's the one who's spending the money, she's in the supermarkets and drugstores," says Sher. He says women will notice the cardboard stand-up displays because "women are very intense shoppers--they walk every aisle."

Initial market research showed, Sher says, that "80 percent of magazine readers don't read books"--a sizable untapped market. And discussions with "20 of the top chains in the country" and interviews with "a lot of housewives, stewardesses and secretaries" convinced him that the potential was there. He joined forces with Norman Goldfind, former publisher of Pyramid Books and now Sabco's president and editor-in-chief, who "took my ideas and put them into reality," backed by a $200,000, 11-city television ad campaign.

Mag-A-Book will be shipping four new titles a month in North America, Europe and Army bases in the Pacific. If readers don't buy them in 40 days, that's it: There are no backlists, warehousing or other services to drive the overhead up. No megabuck investments on untried titles, no distribution nightmares, none of the sinking bottom lines that threaten bankruptcies among traditional trade publishers this year. And, Sher hopes, more ads to accompany those by Exedrin, Bic lighters, Lorillard cigarettes, Doubleday Book Club, and a spate of distaff sundries including Coty perfume, Hair-Off depilatory, Nutra Nail fingernail developer and Permathene diet pills.

In coming months, Mag-A-Book wants to branch into titles from Avon, Warner, Pinnacle and Berkley/Jove, as well as Bantam novels by Irving Wallace and Cynthia Freeman and the first volume in the "White Indian" series. In May, Mag-A-Book will issue its first non-fiction--"The Beverly Hills Medical Diet"--and in June will reprint its first hardcover, "The Mind-Reader."

Along the way, Sher believes, readers will discover that "you read them much faster than a paperback--there's less page turning," with the equivalent of three paperback pages on one magazine page, "all spread out in front of you in double columns." Ron Busch, president of Pocket Books, believes that the format will be a disincentive to most consumers, who do not regard a book as "a disposable item."

Sher, who "was weaned on the book business" in his father's wholesale operation, says that "we're not competing with traditional publishers," because "the publisher still owns the rights to the product." And when the Mag-A-Book comes out, some six months after the paperback is issued, "the author is picking up terrific exposure" in a new market.

Could it draw audiences away from conventional books? "Yes," says Busch, because "the mass-market paperback book is such an endangered species right now, and I don't think this special shape or size is going to create a whole new audience."

"I don't think so," says Louis Wolfe, chairman of Bantam Books. "This is basically not a reading country. So if we can get more people reading, in whatever format, then they may go on to more traditional forms." Irwyn Applebaum, L'Amour's editor at Bantam, agrees, especially if it means new outlets and "up-front placement by the cash register or checkout," which is how Mag-A-Books are sold at local A&P stores.

Ron Overley, manager of District News, which distributes Mag-A-Books in the Washington area, says they will be found "near the reading centers" of stores, but in separate displays "so they won't get lost in the magazine titles." Will it play at People's? "It's too soon to tell," says Overley, but "it's a very interesting concept . . . and the price is right."