It was a Catch-22 of the Cold War.

For more than four decades, the United States and its allies kept a secret list of computers, machine tools, telecommunications equipment and other high-technology products that could not be sold to the Soviet Union or its East Bloc satellites.

But it was by guess or by golly for high-tech companies in the Western alliance. They never knew what products were on the list, which was compiled by 17-nation group that polices technology sales, the Coordinating Committee for Multilateral Export Controls, known as Cocom.

With the Cold War winding down, the East Bloc turning capitalist and Cocom making more advanced technologies available to Moscow, all that has changed. The State Department last month bowed to a Freedom of Information Act request and made the Cocom list public. It acted 11 years after Congress said the list should be readily available.

"It's the end of a long struggle to get a basic working document that should have been available years ago," said Roger Majak, a former congressional specialist in export controls who now works as an industry consultant.

William T. Archey, international vice president of the U.S. Chamber of Commerce, said publication of the list will demonstrate how much stricter the United States is in prohibiting sales to the East Bloc than its allies -- something companies always suspected but never could document. Further, the publication can be used by technology companies to lobby their governments, who have pledged to pare the Cocom list to a basic core of the most sensitive technologies by December.

"That in itself is worthwhile," said Archey, who was in charge of export controls for the Commerce Department during the Reagan administration.

William Root, a former State Department export control specialist who quit in a huff in 1983 over Reagan administration policies, filed the Freedom of Information action in February on behalf of the Industry Coalition on Technology Transfer. Now a private consultant, Root said the 250-page list will be published by OCR International of Rockville so companies can know what they can sell and what they cannot.

Previously, in order to find out if a sale could proceed, companies had to go through a cumbersome, expensive and time-consuming review by licensing authorities in their home countries and by Cocom.

Root said the new information contains "elements that have been published," including a long list of telecommunications products -- model numbers and all -- that have won exemptions from export control requirements for one reason or another.

"It is fascinating information for anyone who wants to know what the competition is," Root said.

The rules were relaxed 10 years ago to allow members to publish lists of products whose sales were restricted, but these lists could not be identified as coming from Cocom. In 1985, the British government published a list it said reflected the Cocom agreements, but Majak noted that list was never considered accurate. Nonetheless, it was the only game in town.

"Practically everyone in the business carries this British list because it is the only one available," Root said.

The new list cleared through the State Department was released shortly before the United States and its allies agreed this month to a sweeping liberalization of the Cocom rules that recognized the changing strategic situation in Eastern Europe and the Soviet Union. Former East Bloc satellites that have turned away from communism, such as Czechoslovakia, Hungary and Poland, now can buy the advanced equipment needed to modernize their economies. Cocom also liberalized restrictions on sales to the Soviet Union, but not as much as it did for Eastern Europe.

Despite the changes, specialists said the list is a valuable document.

Maintaining the secrecy of the Cocom list goes back to the origins of the Paris-based organization, which consists of the United States, its NATO allies except Iceland, Japan and Australia.

The idea of an organization dedicated to preventing the Soviet Union from gaining access to technology was so sensitive in some European nations -- especially France and Italy, which had active communist parties in the late 1940s -- that the existence of Cocom was kept secret.

"To this day," Root said, "every piece of paper that comes out of Cocom has a secret mark on it."