From the heart of Joseph Papp's Public Theater in lower Manhattan tonight, a literary offensive, loaded with verbal turpitude and indignation--"nothing like I've ever seen before," said writer Gay Talese--was launched. It included 25 of this country's best-known authors reading from banned books such as "The American Heritage Dictionary" (banned in Anchorage, Alaska, and Eldon, Mo., "because of the words it contains"), "Mary Poppins," "The Adventures of Huckleberry Finn" and "The Wizard of Oz."

This attack was aimed at city and county school boards of many American small towns, which, ironically, were the inspiration for so many of the works. And it was aimed, by this angry group, at what writer and columnist Nat Hentoff called "small yahoos and video creatures like the Rev. Jerry Falwell."

Lined up behind the speaker's podium like books on a library shelf, the writers--Arthur Schlesinger Jr., Donald Barthelme, John Irving, Erica Jong, Studs Terkel, Grace Paley, John Simon, Calvin Trillin, to mention a few--read selections from what they deemed classic works in protest of the book banning movement, which, according to Hentoff, "is at its highest peak since the days of Joe McCarthy."

The night, entitled "Forbidden Books," was sponsored by the writers' organization P.E.N. and was to be the beginning of the "American Right to Read Movement." Barthelme read from "Huckleberry Finn," which, according to the program, was "removed from English class reading lists" in Montgomery County, Md., in 1981 and in Warrington, Pa., for being racist. Margaret Hamilton--who played the bad witch in the film "The Wizard of Oz"--read a selection from the book, which has been banned from the Detroit public library.

"The people who do this sort of thing--ban books," said "Ragtime" author E.L. Doctorow, "they have not thought much of who they are and what they're supposed to be. I don't think any book could damage any child as badly as unenlightened parents could."

"I hate to use the cliche', but maybe tonight we will raise consciousness," said Hentoff. "Maybe some reporter in Danville, Va., or somewhere will wake up and realize what is going on."

Arthur Schlesinger Jr., wearing his traditional bow tie, read from Aldous Huxley's "Brave New World." "In Huxley's world, history is abolished, religion is abolished. Successful control requires a blank slate," Schlesinger said. "Perhaps then it is not so ironic that I read from this book, which, of course, has been banned in certain areas."

The evening's audience of about 300--who each paid $10 a ticket to benefit P.E.N. and the American Right to Read--jammed into the small theater known for its living-room closeness. The readings lasted for about 3 1/2 hours.

"I remember when I got started in publishing, I was a textbook editor," Toni Morrison, author of "Tar Baby," said backstage before she read from Ralph Ellison's "Invisible Man." "Things happened I couldn't believe. I remember once in Texas a school board wanted to ban Socrates because they thought he was a communist."

"I think you can find small-minded people all over the place," Doctorow chimed in. "I don't think we should indulge in geographical stereotypes."

Before his on-stage reading of Hawthorne's "The Scarlet Letter," John Irving, who wrote "The World According to Garp" and "The Hotel New Hampshire," was talking to a woman from CBS, who to Irving's chagrin had arranged for him to debate a book-banning minister tomorrow on the morning news.

"If I knew I was going to be talking to a book banner, I never would have agreed to this," said Irving. "I'm going to be really mean to him."

"That's okay," she said.

"No it isn't. If I'm paired up with him I'm going to stuff him in the river. I think you should be worried about what I may do on your program."

Perhaps one of the most appreciated passages read during the evening came from Andre Gregory, who starred in "My Dinner With Andre," and who read from the afterword of Ray Bradbury's "Farenheit 451"--banned in a Texas high school in 1981 for being "too negative." He continued despite an unexplainable ringing of the alarm bells during his reading:

"Four, let's face it, digression is the soul of wit. Take philosophic asides away from Dante, Milton or Hamlet's father's ghost and what stays is dry bones. Laurence Sterne said it once: Digressions, incontestably, are the sunshine, the life, the soul of reading! Take them out and one, cold eternal winter would reign in every page."

And Erica Jong, who wrote "Fear of Flying," was asked backstage if the book-banning fever had affected her works. She said, "I don't think my books have even reached the high school shelves."