Here we have a concise history of the Russian state security services from 1917 until approximately 1988 when the book was published. Founded directly after the revolution by Dzerzhinskiy and Lenin, the Cheka, as it was then known, eventually morphed into the NKVD and ultimately the KGB. These respective services were the backbone of the Soviet state and were responsible for keeping it in power. Dziak describes the Soviet Union as a counterintelligence state that came into being through a conspiracy and remained a conspiracy throughout its existence. We learn about the terroristic and deceitful methods they consistently employed to this end, as well as the internal power struggles within the system.
One of the themes of the book is how the post-Stalin Soviets attempted to rehabilitate their legacy after Uncle Joe died by going back to a more "pure" version of the Cheka supposedly represented by Lenin and Dzerzhinskiy. In other words, they tried to write off Stalinism and the NKVD as a cruel deviation from its intended purpose. This, according to Dziak, was mostly a cop-out though as the original Cheka was incredibly terroristic as well. While Stalin's vicious personality undoubtedly worsened things in those years, the framework for terror and repression had long been established by Lenin and Dzerzhinskiy.
I should say that this is not an easy read and frankly I wouldn't recommend it unless you are seriously interested in the subject. The sheer number of different acronyms and organizations is enough to make one's head spin, and it would take some serious study of the entire system to fully comprehend it, I think. Being that the book was published before the fall and thus the opening of the Soviet archives, I'm sure some of the information is also fit for revision. That being said, it seems to me that the historiography of the subject is still rather thin so this would still be considered valuable.