Edgar Doctorow can't understand why some critics are calling his new book, "Loon Lake," difficult and obscure.

"The readers don't seem to have any trouble," he said on a visit here yesterday. "Anyone who watches news on TV can handle discontinuity. Picasso was painting both eyes on one side of the nose 70 years ago. Why should writers be expected to stick with chronological realism?"

It's true. His new novel, like the others before it, goes like the wind. The sentences are clean and tight, even if they don't have any commas in them, and sometimes no periods. He's been writing ever since the third grade, when he decided what he was going to be. He's been writing all through the years as a New York book editor, through the years at Sarah Lawrence and Yale Drama School and even now, at Princeton.

Maybe those critics have been reading photo-realism novels so long they've forgotten Virginia Woolf, and Dos Passos, and Wilder, and Faulkner.

Like all of those writers, Doctorow is basically a wizard. The story just seems to noodle along, characters appear, not much happens . . . and then suddenly, at the end, sometimes as with Wilder in the very last sentence, the writer pulls a string and everything jumps magically into place. The effect can be overwhelming. He has been overwhelming readers since "Welcome to Hard Times" in 1960 and especially with the award-winning "Ragtime."

"I never begin with a plan," the 49-year-old Doctorow said. "It'll be an image, some kind of excitement, a line of energy, and I discover the book as I go along."

Starting "Ragtime," his huge success, through whose panoramic plot various historical figures roam rather disconcertingly, he confesses he hadn't a thought in the world.

"I was in my study staring at the wall. So I started writing about the wall. It was in a house built in 1906. Then I started writing about the house itself. And I was off and running."

This method means a lot of rewriting, of course. There are always many drafts. Sometimes he will do several versions of a single page. Sometimes, as with "Loon Lake," he races through the whole book and then starts over. That whole complex story grew out of a sign he saw as he drove through the Adirondacks. From those two words he projected a private railroad in the woods (there were a lot of them in the Adirondack heyday), a luxurious hunting lodge, gangsters, and on from there.

And isn't this what art is supposed to be all about? The composition of "alternate worlds," as he put it? The invention of "false documents that are more real than true documents . . . like dreams, the original false documents?" m

The image he used at The Washington Post Book and Author Luncheon yesterday at the Sheraton Washington was of the circus clown who somehow scrambles up the high wire after the spangled aerialists have gone and who seems to be giving us a ridiculous parody of their elegance . . . but who turns out to be the most elegant of all.

E. L. Doctorow writes about freedom and the power that freedom gives. In "Loon Lake" he speaks of a mighty industrial overlord, "the impersonal force, the frightening freedom of him." The writer worked long and hard to get that character right, and the central insight he had about him was the sense that he was really, literally free, and therefore dangerous.

Doctorow's books are also about sons searching for fathers. "The Book of Daniel" in particular was a harrowing study of what he speculates Julius and Ethel Rosenburg's sons might have done with their lives after their parents were executed as Communist spies. "Loon Lake" is about a man who invents his father and then becomes him. Yet the author seems to have been close to his own father, who died in 1955.

"I loved my father. He always encouraged and supported me. He had a music and record store in New York, and my brother and I would go there and toot the horns and bang the drums. He lost it in the Depression."

In those hard years (another Doctorow theme), the family struggled but got along fairly well. He remembers vividly the misery in the streets, however, the sweet potato sellers, the ice sellers, the panhandlers, and he was afraid of them. "They gave a kid a sense of danger," he said.

A child's discovery that his father is not God is a disappointment that goes deep. Perhaps the artist, groping in his psyche as he writes, puts a finger on such buried feelings.

In 1970, quitting his editorship at Dial Press to work full-time on "Daniel," he got a visiting writer job at a horrendous pay cut with the University of California at Irvine. He knew it took him at least two years to write a book (600 words in a six-hour day is, for him, moving right along), and with three children from 6 to 13 he worried about the risk, and about how his wife, Helen, would take it.

" i opened the I Ching book, and it said, 'You will cross a great water,' and all she said was, 'Well, obviously that means the Mississippi. Let's go!'"

They never looked back.