The Secret Memoirs of a Sly Ollie North : Books: The former Marine took extraordinary precautions to make sure no one knew he was writing his autobiography. It debuts next week.

Former White House aide Oliver L. North, leading light of the Iran-Contra scandal, has written his memoirs.

In secret, of course. Under an assumed name. And with a code name for a title.

The wraps came off Wednesday, when North’s publisher, HarperCollins, announced that after more than two years of literary skulduggery, North’s autobiography should hit the stores next week.

The book does not contain any major secrets that might touch off a new round of investigations or further implicate Bush Administration officials in the scandal, according to reports of excerpts that are scheduled to appear in Time magazine next week.

But it will provide what HarperCollins promises are “intimate details” of North’s actions in the Iran-Contra saga, as well as his relationships with then-President Ronald Reagan, the late CIA Director William J. Casey and others.

The book’s real title is “Under Fire: An American Story.” But while it was being written, the handful of people who knew about it called it by the code name of “Mr. Smith”--as in “Mr. Smith Goes to Washington,” publisher William M. Shinker said.

North, Shinker and collaborator William Novak met several times at hotels under assumed names to keep the project under wraps, Shinker says. “We did all kinds of things like that,” he says. “It’s amazed me that we were able to keep it quiet so long.”

It amazed other publishing insiders as well. In the hothouse of the New York big-book trade, even the whiff of a major celebrity memoir usually races around town at the speed of light.

The book is being unveiled with a publicity blitz including two successive nights with North on ABC’s “Nightline,” preceded by what is surely a first in literary history: a promotional “teaser” by North at halftime of “Monday Night Football.”

North himself was still under wraps Wednesday, but the publisher issued a statement under his name.

“ ‘Under Fire: An American Story’ marks the end of my long silence,” the retired Marine lieutenant colonel was quoted as saying. “For more than half a decade I’ve stood on the sidelines while others wrote and told about what I did, offering their own interpretations, distortions and, in some cases, inventions. . . . This is the first chance I’ve had to tell the story behind the headlines.”

Actually, North has been anything but silent. He testified for six days before a congressional committee investigating the Iran-Contra affair in 1987, testified in his own trial on conspiracy charges in 1989, testified again in the 1990 trial of former national security adviser John M. Poindexter and has traveled the country making speeches on behalf of conservative candidates and causes, commanding fees as high as $25,000 per speech.

Still, the 416-page book should provide a fuller picture of North’s role in the Reagan Administration’s covert world, including his much-debated relationship with Casey. During his 1987 testimony, North portrayed the CIA director as the mastermind behind his “off-the-books” secret operations to aid the Nicaraguan rebels, known as Contras. But Casey’s friends and aides have denied that the CIA chief, who died in 1987, would ever have done such a thing.

The book also promises new details of North’s private life, including “how his ambition and drive almost destroyed his marriage,” HarperCollins says.

Shinker and other HarperCollins officials stoutly refuse to say how much they paid North for the book. But publishing gossip put the figure “well into the millions,” according to an editor at another house who asked to remain anonymous.

By way of comparison, Reagan, who also played a role in the Iran-Contra affair, got $5 million from Simon & Schuster for his memoirs and a collection of speeches; former White House Chief of Staff Donald T. Regan was paid a reported $1 million by Harcourt Brace Jovanovich, and Fawn Hall, North’s secretary during his swashbuckling years, pulled down a reported $100,000 for her still-uncompleted recollections.

North first contacted HarperCollins in mid-1989, shortly after his conviction on three felony charges stemming from the scandal, Shinker says. After a complicated appeals process, special prosecutor Lawrence E. Walsh dropped all charges against North last month.

“Every major publisher in the country, including myself, had expressed interest” in a book by North, Shinker said. “I don’t really know why we were chosen. . . . But I think, frankly, the fact that we are owned by Rupert Murdoch (the Australian-born communications magnate and sometime patron of conservative causes) made Ollie feel this would be a simpatico place for him.”