This has been an extraordinary year in the international espionage trade. An epidemic of spy scandals and high-level defections has rocked the intelligence services of East and West Germany, the KGB and—to a lesser extent—the CIA. In a climate of gathering suspicion and paranoia, the flight of each double agent has seemed to accelerate the unraveling process, leading other spies to run for cover. In May, Sergei Bokhan, a top Soviet agent in military intelligence based in Athens, crossed to the West. Three months later Oleg A. Gordievsky, the KGB's station chief in London, closed out more than 10 years of perilous double agentry for the West and defected to British authorities. Then in late summer, while the U.S. intelligence community was still assessing the damage from the Walker spy family's alleged leaks to the Soviets, Hans Joachim Tiedge, a top West German counterintelligence officer, fled to East Germany, a country he had secretly served for several years. Last month it was disclosed that Vitaly Yurchenko, one of the KGB's most powerful spymasters, had defected to the U.S. during a July visit to the Vatican. The Soviet defector identified former CIA officer Edward Lee Howard as a KGB mole. Howard was under FBI surveillance September 21 when he fled from his Santa Fe home. For an explanation of these upheavals in the murky world of espionage, correspondent Maria Wilhelm interviewed George Carver, a retired 26-year veteran of the CIA and a senior fellow at Georgetown University's Center for Strategic and International Studies.

How serious was the alleged betrayal by former CIA agent Edward Howard?

If he was actively working with the Soviets, that would have been extremely serious because he was in a position to expose CIA personnel, operations and methods. However, Howard's defection has not created problems of the same magnitude as those the Soviets have suffered through the defection of their far more senior officers. Howard is a hailstorm. Bokhan, Gordievsky and Yurchenko are earthquakes. Internally the Soviets are going to do some housecleaning and some tightening that will be absolutely savage. I think some people are going to come to very untimely ends.

Are the recent defections connected?

Though they're not necessarily related, it's tempting to think the first defection set in motion a chain of events. But to demonstrate this you must know the precise timing involved. For example Gordievsky's defection could easily have generated others. He was an extremely senior KGB officer, and his defection would put the Soviets in a very sour mood. They would try to find out if they had any other weak links in the chain and would begin pulling in guys from around the world. Now the KGB's minions are not known for being subtle or gentle, and some of these guys just might think twice about being questioned, deciding to fold up their tents and get the devil out.

Why weren't valuable double agents like Yurchenko or Gordievsky left in place?

If either one felt he was about to crack under the strain, he'd be pulled out. A senior double agent puts his life on the line every minute. Who's to say what made him nervous, what pushed him over the line? The notion that you can just leave him in place because he's very productive is childish. The risk may have just gotten too high. If, for example, Yurchenko had been left in place until the KGB collared him and he wound up with a bullet in the base of his skull, then the next KGB agent a CIA case officer tries to recruit might be extremely skittish.

After the defection of Hans Tiedge, how can we entrust secrets to West Germany?

I used to be chairman of the U.S. Intelligence Coordinating Committee in West Germany and I had to live with this problem every day. You have to recognize there are fundamental weaknesses in the West German security structure. For instance any German has a right to seek asylum in West Germany, which makes it very easy for the East Germans to position their agents in the West. But the West Germans are important NATO allies, and cooperation with them is essential. Somehow you have to thread your way through that minefield.

How do you make a contact with an important agent in the first place?

Who knows? How do you pick up a girl, particularly if she's married to someone else? You're dealing with similar problems, particularly if her husband is a crack shot with a notoriously short temper.

What responsibilities do we have for accepting an agent from the other side?

No intelligence service can function very well unless it has a good reputation for looking after its people. That's one thing the Soviets and East Germans are meticulous about. After someone like Yurchenko has been useful to us, we're not going to say, "There's where you apply for food stamps." No, you protect such people for the rest of their lives. Yurchenko and Gordievsky will soon be tried in absentia for treason and sentenced to death. It may take the KGB 30 years, but they are unlikely to close that file until they've at least tried to carry out the sentence of the court.

Do you think others will defect along the same lines?

The Soviets must be saying, "Whom can we trust?" If you're a top-level KGB manager, you're damned if you do and damned if you don't. If you send out ideologically blinkered thugs, you're not going to reach the targets you want. If you send out polished sophisticates, you're liable to lose them.

How does the CIA monitor its agents?

Without intruding on private lives and not slipping into Big Brotherism, every supervisor keeps an eye on his subordinates. Are they drinking too much, sleeping in too many beds in which they're not normally supposed to be sleeping? You're not checking on their morals, just whether or not they're under too much stress or subject to blackmail. Also, the CIA makes extensive use of lie-detector tests. The staff accepts that this goes with the territory.

How much is the public told about the defections?

There's a conflict between an intelligence service's need for secrecy and a free press. My private answer would be that I hope the public is being told less than 100 percent of the full story.