Richard Kiley stares out into space. He scarcely ever looks at you when he's speaking. He looks as if he'd rather be anywhere in the world than in the press lounge of the Kennedy Center which is where, as it happens, he is. He looks, in a word, exhausted.

"Well, you'd be exhausted too, if you were playing this &$ role," he retorts, his eyes now trained on his sneakers.

Richard Kiley is "Man of La Mancha." Once again. He started it in New York back in '65 and got a Tony for it, but he still thinks it's "absolutely marvelous . . . a delicious role with endless, endless, untapped corridors. One uses want one has learned when one returns to a part like this."

And what has Kelly learned in the intervening years?

"I don't know. I guess a little about living."

But what, specifically?

He shrugs. "I can't articulate that."

In any case, he'll be incorporating whatever it is he can't articulate into the role of Don Quixote for a total of 40 weeks, starting with the National Theater, moving on to Broadway, and then the rest of the country.

He shifts uncomfortably on the couch and pulls at his nose. At 55, it seems, Richard Kiley is every bit as shy as he was as a high school kid growing up in Chicago.

"I really got into acting comparatively late," he says. "I was a very shy kid and disliked the idea intensely. But in high school I got the idea of dong 'The Mikado' with Steve Allen - and I got th bug."

Kiley starred: Steve Allen was in the chorus "which infuriated him." For the first time Kiley attempts a smile. It fades almost instantly.

"There's a curious line of demarcation with the footlights," he murmurs, almost to himself. "If you are shy, it's almost an internal Maginot Line, I think that the proseenium - that protective arch - has a kind of magic about it, a removal factor.

"One outgrows that. Now I'm capable to talking to large groups. I'm not as terrified as I was when I was 16. To me the stage is magical - that vague amorphous mass out there seems to be laughing as one."

He thinks that over, then says, "It's always easier to communicate with an audience on stage rather than making a recitation in school. And there's an additional removal with the character. I always loathed being out there being myself. I felt" - he chuckles drily - "I felt like I was in 'Oh Calcutta!" or somehing."

Kiley has all his protective garments on - and then some. A blue sweatshirt, blue slacks and the blankest of abstracted expressions, as if he had removed himself not only from the press lounge of the Kennedy Center, but from th entire present tense with all its pressures and demands. And yet, he's been in the business a very long time. Back in 1953 he made his first Broadway appearance in George Bernard Shaw's "Misalliance." Lately he's been seen here in "The Master Builder."

"I have had," he says, choosing his words, "a marvelously resilient career. There have been dry periods, but never one that resulted in my eating the tops of my shoes."

"When you were about 3," he continues coolly, "I was doing live TV, 'Studio One' - all those things . . ."

And Broadway, of course.

"It can get a little heavy doing the same type of leading men roles. I was in 'Redhead' with Gwen Verdon (for which he got his first Tony). I was with Diahann Carroll in 'No Strings.'

"Which is not exactly chopped liver. But I've always felt I was a character actor."

What made him feel he was basically a character actor?

"I don't know," he replies, visibly annoyed. "What makes you feel you were always a girl? It's an intuitive thing you sense about yourself and your gifts. Until you find yourself in the right slot."

Being a character actor, of course, is another way of saying that pubescent girls and grandmothers do not necessarily drop into dead faints when the star enters their line of vision.

"In a way that's a two-edged sword," says Kiley. "One's ego is always a goofy thing." He mimics the star-struck, "Oooo . . . Look who THAT is!"

On the other hand it can be enormously unnerving if one is constantly hiding behind dark glasses and holding the collar up.

"It's very, very bad, very hard for one to do that. I imagine that Newman and Redford find it very tedious to go into a restaurant.

"With me, people come and say, 'I know you from somewhere. I think I met you at the office.'"

A trace of a smile; he summons a Texas accent to his aid. "Once I was in Dallas, and someone came up to me saying, 'By God, that's a helluva god-damn thing. I met you in Chicago, and you were losing so much money over a poker game.'

"And I said, 'No. I'm sorry. That wasn't me.'

"And he said, 'Now - that was you. We were at a toy convention and it was a helluva night.'

"And I said, 'I'm sorry. I wasn't at the toy convention.'

"And he said, 'Aw-w-wll right, goddammit. The hell with you.'"

Kiley shrugs again, they says midly, "Unless you tell people. 'You saw me on TC" - if you just want to preserve your irivacy - people sometimes get their hackles up."

He hasn't made a whole lot of movies, but he will be appearing in "Looking For Mr. Goodbar" as Diane Keaton's father. He elected not to read the book on the advice of the director.He is asked if he ever read "Don Quixote."

"Once, all the way through." In the vacant pause, he adds, "You know - it's a curious thing about that novel. It would be an absolutely perfect format for a TV show. Because everything in it is episodic. It would be superbly done."

Another pause. Then: "If each episode were done for about $1 million in living color. Then it would make a glorious show. But the thing is it never really worked as a play or a ballet or an opera."

Then how come it worked as a musical?

"That's a good question." He allows the heady praise to sink in. "That's because Dale Wasserman (who wrote the show) decided to tell the story of Cervantes who had an extraordinary life. And Wasserman very cleverly suspected that Don Quixote was Certantes. That juxtaposition of the Cervantes story with Don Quixote story is rather exciting."

It turns out that what Richard Kiley most likes to talk about (or at least talks about in greater length) is Don Quixote. As opposed to Richard Kiley.

"There's a kind of general sense with some people," he says, "that one identifies totally with Quixote. That one's head is in the clouds."

He imitates an admirer: "'I really feel that facts are the enemy of truth.'"

Kiley gazes off into the distance.

"Of course in an odd way I feel the same way. I feel our lives are too circumscribed by facts. Some of physics is bearing out. That what one sees is not necessarily what is."