INSIDE THE AQUARIUM: THE MAKING OF A TOP SOVIET SPY by Viktor Suvorov (Macmillan: $17.95; 256 pp.)

Anyone who has lived in the Soviet Union quickly learns that life can imitate bad art. Where the ways of the system are concerned, nothing is too outrageous or absurd. The chilling opening scene in Viktor Suvorov’s “Inside the Aquarium” demonstrates that. A training film for Soviet spies features a lesson on the penalty for deception: One of their own agents is shoved into a crematorium’s oven alive. The fact that this is ideally suited for a Hollywood production caricaturing the evil empire is, of itself, no reason to dismiss it as too far-fetched to be real.

Suvorov is the pseudonym of a defector from the GRU, the Soviet Union’s military intelligence organization, who now lives in Great Britain. His earlier book, “Inside the Soviet Army,” was based on his regular military service. In his new book, he chronicles his recruitment by “the Aquarium,” as the GRU’s headquarters is known, his training and subsequent relatively brief career as a spy based in Vienna. It was work he was well-suited for. “A taste for a life of conspiracy is not like any other, and I like it,” he writes. “I understand and appreciate it.”

Since the GRU’s operations are so secretive as to make the KGB look like a virtually open institution, Suvorov’s account cannot be verified independently. The only yardstick is its internal credibility. I found my own feelings on that score slowly moving from skepticism to general, if far from total, acceptance.

Suvorov is prone to sweeping overstatement, claiming, for example, that GRU agents have not missed a single exhibition in the world for the last half century. Initially, too, he raises doubts by painting himself as almost recklessly defiant of authority, getting away with such behavior on more occasions than seems possible. The book suffers from other drawbacks as well. Suvorov’s taste for conspiracy extends to keeping the reader in the dark about the nature of a mission he performs that is crucial to winning him a key promotion. And the subtitle is somewhat misleading: In mafia parlance, which is far from inappropriate when discussing the methods of the GRU and the KGB, he was more of a soldier than a capo in the spy business.

But it is Suvorov’s struggle to rise within the organization to the rank of a Viking, the term applied to spies who run their own missions rather than perform the thankless backup work for others, that makes this the fascinating book it is. Whether or not some of his larger claims are accurate, Suvorov offers a compelling portrait of the psychological training of spies. They learn that everything and everyone is suspect, especially their closest colleagues. Paranoia (a seemingly trivial slip can produce instant retaliation from above, abruptly ending a promising career) and rationalization (the mentality of the concentration camp guard that if I do not execute every order, however bestial, someone else will) are instilled with devastating results.

What makes Suvorov’s rendition of this training convincing is that he provides a case study, his own, of how those results are achieved. He does not paint himself as morally superior. To survive, he sets up colleagues, staging provocations that can only lead to their destruction. It is only when he sees that he, too, is doomed by the system that consumes most of its own that he makes his bolt for freedom. There is an admirable lack of pretense that his were lofty motives.

Suvorov has an instinctive feel for the dynamics of power, privilege and fear. His descriptions of cliques, how they are formed and how they advance within political and military organs, or of the almost capitalist competition between the GRU and the KGB are incisive, without being particularly analytical. He was a spy dedicated to action not serious reflection. His story, straightforwardly narrated, nonetheless tells us a great deal about the nature of the system that spawns an organization like the GRU.

Nagorski, Newsweek’s Bonn bureau chief, is the author of “Reluctant Farewell: An American Reporter’s Candid Look Inside the Soviet Union” (New Republic/Holt, Rinehart & Winston).