All over the English-speaking world, A.L. Rowse is known as a very distinguished Oxford historian who is also a little bit - as they probably don't yet say at Oxford - far out.Among his contributions to knowledge, the most notable is his solution to one of the biggest mysteries of western culture - the identity of the Dark Lady of Shakespeare's sonnets.

According to Rowse, he has established beyond doubt that the lady in the poems was Emilia Bassano, daughter of one of the queen's Italian musicians and wife of another musician who was an ancestor of Tennessee Williams.

Other scholars, persisting in error, say that what Rowse has done in his study of the documents is to give an impressive demonstration of how to add two and two and make seven. Rowse's answer to his critics is characteristic: "They are not entitled to an opinion."

Rowse has no trouble with self-doubts or lack of energy. If a demand ever comes up for elderly gentleman as go-go dancers, he could make a new career. At 75, he has the nerve and the coquetry. He is anything but the aloof Britisher.

Rowse is a toucher. If he explains to you the concatenation of dates and events that proves his theory about the Dark Lady-in a rapid fire of erudition that only another Oxford don could follow-he is communication his points unless he has a grip with both hands on your shin bone.

In fact, a shy type in close converse with a giggle that he is not an Eng the professor did have a little British sloofness.

When he straightens out your ideas on the Elizabethan Renasissance or socialism in today's England, he adjusts your kneecaps at the same time. If this exuberant out-goingness is called to his attention, he explains with a giggle that the is not an Englishman-really he is a Cornishmen. "As for you, dear, you can't be anything but one of those New England Puritans."

"The Queen," says Rowse who speaks of Elizabeth I as though she were less remote than her current namesake "hated the Puritans. She always referred to them as "the brethren in Christ.' They were very unpleasant people. They would have closed the theaters . . ." The most glorious legacy of those theaters is the foundation of Rowse's, new book, "The Annotated Shakespeare." Actually three books boxed, this is the complete works with explantory notes and introductions by Rowse to each of the plays and long poems. Because Rowse, along with his qualities as a fount of learning and a provocative kook, is a superb writer, this looks like the hot gift book for Christmas.

On this day when he is holding forth in his Manhattan hotel room, Rowse is also scheduled for a two-hour interview with Dick Cavett, in the evening, he will lecture to the English Speaking Union with his fan, Jackie Onassis, in attendance, "She called me the other morning," Rowse says. "She has the most entrancing voice. You have a nice voice, too, but it doesn't absolutely seduce me."

Above his spectacles, Rowse has a high, broad forehead, and what is behind it has created for him an extraordinary career.

The son of a miner, he won a scholarship to Oxford back in the days when the usual qualification for entry was blue blood. Striving against the odds, he acquired a dueodenal ulcer at 19. He now thanks the ulcer for his long life. It made him a teetotaler and foredoomed him to wrat he calls "a pure life." It also slowed him down. "I have a tendency to overwork," he says, "and if I hadn't been winged by the ulcer. I might have worked myself to death."

Under the circumstances, he has written only 40 or 50 books. Three of them were works of autobiography, of which one, "A Cornish Childhood," was an enormous best seller. "I'm hardly human, I'm so highbrow," he says, emphasizing this with a squeeze of the thigh, "but the public can read me because I'm alive."

The big reason why the critics of his theories about Shakespeare are talking through their hats, Rowe says, is that they are either historians or specialists in literature. He, on the other hand, is learned in both fields. On top of that he is a poet. "I had a rather lovely poem on the death of the pope in a recent issue of the Times Literary Supplement," he says. "Do look it up, dear; I can tell you'd like it."

Having spent a life immersed in the age of Elizabeth I, Rowse contemplates the present "with extreme depression."

In the former era, he points out. "England was going up in the world. The whole society was tingling with excitement and achievement-of which the biggest achievement was starting English-speaking America." Contrasting the reign of Queen Bess with what goes on today shows us, according in Rowse, that "democracies are ungovernable. Democracy is something we've all got to accept, but I'm not taken in by any of the humbug."

If he could go back by time machine to the age he knows so well, what events in particular would he like to witness with his own eyes?

"Well, I would like to see the Armada sailing up the Channel," he says, "I should think that would be a rather grand sight, don't you?" He also would like to have seen and heard Herself sitting on horseback at Tilbury and rousing the troops with one of the great pre-battle speeches of all time. "And I'm the only one," Rowse says, "who knows what she sounded like. There was a French ambassador who wrote a description of her voice. It was high, sharp and authoritative, not at all like Mrs. Onassis."

In his spoken manner, Rowse is all bantering irony and busy hands, except when he talks about what he knows as a scholar or thinks he knows.

Then the facts and dates pour out with a speed and copiousness that make the non-learned listener's head spin. Observing this, Rowse again switches gears. "Why don't you ask me about my sex life?" he suggests. All right, if this holds a message for the world, what about it? "I wrote a book," he says, "called 'Homosexuals in History.' The Gay Lib people thought I was hostile because I laughed at them. The fact is, sex is a comic subject. There is nothing in life which makes us so ridiculous."