THE UNIFIED Germany coming into existence on Oct. 3 will be burdened with a dark inheritance and thorny problem from East Germany's past -- how to treat the 5 million dossiers compiled by Stasi, the East German secret police, on millions of East and West Germans for nearly 40 years.

This is the bitter harvest of the East German government's secret police work, which remains in storage in East Berlin. East German archivists are contending with reels of computer tapes and file cabinets containing reports from telephone taps and postal intercepts; they are also combing through pages of surveillance reports from agents who spied on schools, businesses, hotels, hospitals, libraries and even private homes. The dilemma deepens too because the files include the names of coworkers, friends, neighbors and relatives who spied on each other -- sometimes involuntary, often not.

East Germany's first democratically elected government, which will be dissolved with the birth of the unified Germany, has reached agreement with the West Germans as to how this can be resolved. They have agreed to keep the Stasi files centrally deposited in the east after Oct. 3. And to little surprise, the governments also have decided against outright destruction, since the files are yielding valuable information about the Stasi's assistance to German, PLO and Libyan terrorists operating against Western targets -- including the United States. The files are also helping both Germanys ferret out former high-level agents who remain in place on both sides of the border.

Yet for each helpful discovery there are hundreds of pages of hearsay, groundless rumors and outright slander and lies. Consequently, East German civil rights groups have demanded that citizens be given access to their files, not only to challenge the contents where necessary but also to prevent harmful information from following them into the new Germany. While initially fearful of recriminations throughout the populace should that happen, the two governments have reached agreement that citizens affected should be granted the right "as soon as possible" to get information about -- but not necessarily access to -- their own files. At the same time, they have agreed that the rights of third parties or sources should not be violated through information disclosure. But in a nod toward widespread East German concern, East and West Germnay have decided also that intelligence services of the new Germany -- and Western and Eastern intelligence services -- should not be given access to the old files.

To ensure that these new rules are correctly applied, the agreement calls for the appointment of a board dominated by East Germans to operate the Stasi files program. While the unification agreement will not eliminate the new Germany's inheritance, it does offer the promise that beginning Oct. 3, citizens of the new Germany, especially those from the old East Germany, may be able to lift the shades and shed some light on their past.