Espionage watchers consider the early 1990s a low point for the National Security Agency.

Around that time, the Internet was beginning to change how people communicate, becoming a new tool for everyday life. But while the rest of the nation was e-mailing each other, NSA was still delivering top-secret intelligence reports to Washington inside pizza boxes.

An agency that in its heyday had helped create the first computers had become appallingly low-tech. Gen. H. Norman Schwarzkopf even complained about it during 1991's Persian Gulf war when he said intelligence reports on Iraq's military were taking too long to reach his hands.

That has all changed recently with the development of an internal computer network for spies called Intelink, which brings up-to-the-minute spy data to hundreds of thousands of spies, diplomats and soldiers in the field, as well as Congress and the White House.

Completed in 1996, Intelink has become an invaluable tool for the 13 intelligence community agencies that use it to disseminate and share their secret information.

Intelink consists of highly classified data that users access at the click of a button. Data that once took hours to reach Washington now cross the globe in a second.

Just like logging onto America Online or the World Wide Web, intelligence analysts and military personnel log on to Intelink's home page, where they see a map of the world and can click, say, Bosnia to access intelligence reports, video clips, satellite photos, databases and status reports. Users can "chat" online with other spies or exchange e-mail on a topic.

The evolution of NSA's in-house Internet coincides with a new philosophy: Why struggle to be a technological leader when it's easier and cheaper to buy all the cutting-edge software we need from Microsoft and others?

How the NSA changed

The story behind that transformation is detailed in a new book by a former top NSA official -- a book noted as much for the fact that it was published at all as for its content.

When Tom Martin started working for NSA in 1960, he signed a letter promising never to write a book about his super-secret employer. In a sign of changing times in the intelligence community, Martin unveils previously classified details about how NSA spies on the world.

And he does so with NSA's approval. Martin's book pulls back the curtain on the gears of NSA's machinery, providing a rare nuts-and-bolts look at how today's high-tech spies do their job.

"Top Secret Intranet: How U.S. Intelligence Built Intelink -- the world's largest, most secure network" is also a fascinating glimpse at the slow and sometimes reluctant thawing of an obsessively secretive agency that once denied its own existence.

Three pages of signatures are attached to the 1996 letter that gave Martin permission to write. But he and others are amazed that NSA allowed into print so many secrets. Many of his former colleagues declined to be interviewed by him for the book. Some are still angry.

First of its kind

"A book about NSA has never been written by an insider," Martin says. "It was tough getting through the system because people were opposed to it. There is a school of thought that says you wear your trench coat and your dark glasses and you don't say anything."

Martin retired from NSA in 1997 and now works for a Reston, Va.-based company that does contract work for the agency. He still has his top-secret clearance, but he believes it is possible to protect national security while still giving citizens a glimpse at where their billions in tax dollars are being spent.

"We can have more openness and not compromise the family jewels," he says. "There isn't a bad word in the book about the agency. I revere the agency."

Martin's efforts to write about NSA were aided by a handful of top NSA officials, particularly former deputy director William Crowell.

He finally gained approval in 1996 from Gary L. Grantham, then the agency's acting director of policy, whose letter said Martin's request was approved based on "the potential benefit to the National Security Agency."

"This book would provide another good opportunity to document our efforts to improve government through the use of technology," Grantham wrote.

A former NSA director, retired Adm. William O. Studeman, agreed to write an afterward.

"The intelligence community has tried to be a lot more open about the things it's doing," Studeman says. "It's trying to demystify its business. It's a fine line to walk."

NSA did reserve the right to review Martin's manuscript and delete sensitive material. But Martin says surprisingly little was redacted. Not even Martin's criticisms of NSA's "old methods" of intelligence dissemination were excised.

Archaic dissemination

Martin describes how NSA has long relied on cutting-edge computers to intercept the phone calls and radio transmissions of foreign nations, and to break their secret codes. But then it processed the so-called intelligence "product" and shared that data with its "customers" in the intelligence community in daily reports called the SIGINT (signals intelligence) summary, or SIGSUM. It looked like "a club newsletter."

"It was a joke. We were the laughingstock," Martin says. "The old story that intelligence was delivered in pizza boxes, it was true."

The changeover began in 1994, when Central Intelligence Director R. James Woolsey and Deputy Defense Secretary John M. Deutch signed a letter (reprinted in Martin's book) recommending that "INTELINK be the [Intelligence] Community architecture for sharing and disseminating intelligence."

Studeman disagrees that the situation was as appalling as Martin describes it -- "I don't believe we were ever that far behind industry" -- but considers Intelink an important new tool.

"We were struggling at the time for ways to improve dissemination," he says.

Using off-the-shelf commercial software to create its new network, instead of working for years to create in-house software, was a valuable concession. "In today's world, we're not the inventor, we're a fast follower," he says. "We're riding the commercial wave."

Threat from inside

In the coming years, the challenge for NSA will be controlling the explosion of top-secret information on Intelink. Because the network is connected by secure Department of Defense phone lines and satellite connections, it is allegedly impervious to hackers.

"Although people try every day," Martin says.

The larger challenge will be internal security -- protecting Intelink's information from people willing to sell out their country by exposing U.S. secrets.

Already, there are strict limits on how and where spies can cruise the Intelink. "Data classified NATO SECRET cannot be posted on Intelink," says one warning. Another bans sexual innuendo and "virtual dating." Electronic conversations in Intelink's "chat rooms," such as the Organized Crime Web Page, are constantly monitored by a crew at Fort Meade.

"So, it has all the advantages of the Internet, but all the disadvantages," Studeman says. "The problem you have to deal with is the insider gone bad."