Suvorov is a former Soviet intelligence officer who defected to the UK in 1978. According to the author, while studying as an intelligence officer, he became intrigued by the question of why all criticism of Stalin had been ruthlessly quashed with one exception: the failure to detect and prepare for the Nazi invasion during World War II--Operation Barbarossa. Although Suvorov did not have direct access to many of the key records, he was able to obtain access to other records that indirectly or partially illuminated the answer: that Stalin was unprepared to defend against a Nazi invasion because he was neck deep in preparing for a Soviet invasion of Germany. Stalin's plan was to encourage Germany to start a war with the Western European powers and, when Germany was exhausted and deeply involved in the European war on the Western Front, invade Germany in derogation of the treaties and agreements it had made to lull Germany into a false sense of security.
In the first portion of the book, Suvorov spends considerable time detailing how technologically advanced were much of the Soviet equipment at the beginning of World War II compared to its peers--particularly as to tanks and aircraft. I won't bore you with details, but to just take one example was the T-34 tank, which served throughout the course of the war. According to Suvorov, it had superior armor, a more powerful engine, and better design of the tracks (e.g., an optimum width to allow it traverse a wide variety of terrain) than any contemporary tanks. I'm no tank expert, but even to the untrained eye, the configuration of the T-34 is certainly closer to modern tanks than what we see from Germany or any of the allied countries at the time.
Additionally, according to Suvorov, the Soviets had aircraft, tanks, trucks and other equipment in vast numbers, and the industrial capacity to produce more in high quantities. But where did these disappear to when the Nazis invaded? If you have studied Operation Barbarossa, one of the facts that stick out was the shortage of military equipment and arms. For instance, histories of the beginning of the Battle of Stalingrad describe Soviet troops being rushed into battle without even adequate arms; many had no rifles and had to scavenge rifles from fallen comrades.
This is where the documents Suvorov was able to access start to fill in the blanks. According to the records, reports, and even bits and pieces from various biographies, speeches and memoirs of senior Soviet officers, huge depots of arms and munitions had been moved up close the Soviet borders, many stockpiled in secret. The Soviets had torn down much of their border defenses, including fortresses and pillboxes, trenches and minefields, to allow the easy passage of their troops. Stalin's plan for invasion had been to make his initial thrust into Romania in order to cut off Germany's access to its oil supply, followed by thrusts elsewhere. Because of the mountainous nature of the terrain, the troops that had built up along the USSR's south-western border were mostly mountain troops; and many of the troops destined for the western border with Germany were still being moved when Hitler assaulted. Moreover, the Soviets were so focused on attack that they had not planned or trained for a defense from an invasion. Thus, when the Nazis attacked, they were able to quickly overrun or destroy the Soviet depots.
There are some other factors that seem to support Suvorov's theory. First, and one that he spends time on, is that the USSR used similar tactics--guarantees of neutrality followed by invasion when the enemy was weak--on other occasions, including the USSR's invasion of Japanese held territory after Japan was already largely defeated by the U.S. In fact, according to Suvorov, the strategy was almost identical. The USSR had signed a neutrality agreement with Japan promising not to fight against it. It then secretly moved men and material close to the borders. It dismantled defenses to make it easier to cross the border. And then when it invaded, it was with overwhelming force with supplies already prepositioned near the advancing troops.
Second, it explains the motivations of both Stalin and Hitler proceeding Operation Barbarossa. As we know, prior to WWII, the USSR and Germany had entered into a non-aggression pact and had agreed to splitting up Poland and establishing what other Eastern European countries fell within their respective spheres of influence. As part of the agreements between the USSR and Germany, the USSR promised to provide raw materials to Germany. It was these agreements, and Germany's invasion of western Poland, that enabled Germany to prosecute a war against Western Europe, and, in fact, sparked that very conflict. But, wrapped up with the war in the West, why would Hitler suddenly turn to strike the USSR? Was it because he thought that the war against Britain was a done deal? Or, as Suvorov suggests, did Hitler suddenly become aware of Soviet intentions to invade and realize that the only defense would be to strike first?
Another point that Suvorov raises is that, notwithstanding the overtures of peace that Stalin publicly made, speeches made in secret to Soviet military leadership, planning, war games, and Soviet doctrine, all emphasized fighting on the enemy's territory, not defending the Soviet Union. That Stalin would take such a position should surprise no one--even when the Bolsheviks were engaged in the Russian civil war, they were still fomenting unrest in the West, and very nearly brought Western Europe to revolution during the 1920's. Moreover, Marxist doctrine--and the primary difference between Communism and National Socialism--was the belief that Communists had to "liberate" the world. It was an expansionist philosophy at its core. Thus, for Stalin to secretly plan to betray Germany and invade was wholly consistent with Communist teaching.
The final issue that Suvorov discusses was how did the USSR fail to see German preparations for Operation Barbarossa. This is actually a quite extraordinary thing since it is well known that the USSR had intelligence sources high in the German government, and probably even Hitler's inner circle. Suvorov asserts that the USSR's intelligence assets did see the preparations and warned Stalin of the impending Nazi strike. Only, Stalin did not believe the reports because it seemed so incredible to him that Hitler would make such a suicidal decision to open a second front of the war when he didn't have the equipment to support such an invasion, including a complete lack of long-range bombers that could strike Soviet industry east of the Urals, inadequate supplies of fuel, and his troops didn't even have cold-weather clothing.
In conclusion, Suvorov sets out what I believe to be a compelling case that Stalin had maneuvered Germany into a war with France and the UK for the purpose of weakening the West and opening it to Soviet invasion. If Suvorov is correct, Germany's strike was so crippling to the USSR because the USSR had moved much of its war material to the front allowing it to either be captured or destroyed in the early phases of Germany's invasion. But if it had not been for Operation Barbarossa, the USSR would have been able to deliver a crushing blow to Germany's back, and probably would have had the initiative and momentum to take the Continent.