Ronald Reagan has chosen Edmund Morris, the Pulitzer Prize-winning author of "The Rise of Theodore Roosevelt," as the chronicler of his life and presidency. Accordingly, he has granted Morris unlimited interviews and rare access to White House meetings.

Details of this biography's special arrangements have been confirmed by Reagan family friend Michael Deaver and other sources.

The bidding for the Morris biography of Reagan has escalated past the $2 million level, sources say, and is still rising.

"This isn't just another biography," said an executive at a major publishing house. "This is a book that has the imprimatur of Ronald Reagan."

The price for the Morris book is expected to exceed the more than $2 million advance Harper & Row paid for former Office of Managment and Budget director David Stockman's memoirs. That book had already exceeded the previous records for books by public officials, including the slightly more than $1 million Random House paid for House Speaker Thomas P. (Tip) O'Neill's autobiography, the $1 million Bantam Books paid for Geraldine Ferraro's campaign story and the $900,000 advance Simon & Schuster gave former United Nations ambassador Jeane Kirkpatrick.

Morris, whose masterful first volume of his projected three-volume life of Theodore Roosevelt was published in 1979, is a native of Kenya.

His wife Sylvia is the author of "Edith Kermit Roosevelt," a biography of Roosevelt's second wife. Sylvia Morris, moreover, is writing a biography of Clare Boothe Luce. The Morrises live on Capitol Hill.

The Reagan biography is rare among presidential biographies in that present and past will be merged with the presence of the on-site historian. Historians in the past have worked in the White House -- Arthur Schlesinger Jr., for example, was an aide in the Kennedy White House -- but Morris will be there only in his capacity as a historian.

As if to underline this, he accompanied Reagan to the Geneva summit.

Morris could not be reached for comment.

Morris first came to the president's notice shortly after his 1980 election when Selwa (Lucky) Roosevelt, the State Department's chief of protocol, sent the Reagans copies of the Morrises' books.

"I sent a note, writing that these books are about a devoted couple by a devoted couple to a devoted couple," she said. Mrs. Roosevelt's husband is Archibald Roosevelt, Theodore's grandson. The Morrises met the Roosevelts while they were conducting their research.

The impetus for the unusual Reagan biography came from a dinner party held on Feb. 14, 1983, at the home of Sen. Mark Hatfield (R-Ore.).

"I was concerned about the need for scholarship to be in proximity to history," said Hatfield. So he invited President and Mrs. Reagan to meet with Arthur Link, the biographer of Woodrow Wilson; George Nash, biographer of Herbert Hoover; Frank Friedel, biographer of Franklin D. Roosevelt; Librarian of Congress Daniel Boorstin; and Edmund and Sylvia Morris. The scholars discussed their common wish to have known their subjects. Morris expressed his desire to have known Theodore Roosevelt by means other than dry documents and letters. The president, "fascinated," said Hatfield, stayed late into the evening.

Then-deputy White House chief of staff Deaver, who was aware of the Hatfield dinner, spoke with Selwa Roosevelt about the Morrises. "We arranged a dinner where the Reagans and the Morrises and I met each other," said Deaver. "They liked each other. The chemistry between the president and Morris is so good. Nancy liked him very much. They both liked the Teddy Roosevelt book. And the president said he'd be delighted if he'd do a biography."

The Morris book is thought of by those closest to Reagan as "an important part" of his historical legacy, said Deaver. "I've asked Reagan countless times how he'd like to be remembered. He says, 'Gosh, I don't like to think about it,' " Deaver said. Now Morris, present on the scene, will help "memorialize the Reagan presidency," according to Deaver. But Deaver said that Morris' effort will not substitute for Reagan memoirs.

Even while Morris travels with the president, the proposal for his project is being circulated among publishers.

Bids are being received by his agent, Georges Borchardt, who has sent a two-page letter around, emphasizing Morris' special access.

"We know this is going to be an important book by a very talented writer," said a publishing executive. "The judgment that has to be made ultimately is how much of an investment makes good business sense."