Many of the intelligence secrets remain unsolved. Atanas Kremenliev describes, in his words, a small, insignificant part of what he saw and experienced in the corridors and labyrinths of Bulgarian intelligence, but in fact he wrote a textbook on intelligence. It examines all countries and specifics of intelligence - the history of intelligence in different countries, the specifics of ideology, politics, confrontation, religion, terrorism, the means it uses - agency, technical means, cover-ups, money, sex and more. , the work of the Bulgarian intelligence in different countries, the cooperation of the Bulgarian intelligence with the intelligence in the socialist countries, the betrayals in the intelligence, the leaders of the Bulgarian intelligence, the reviews of foreign intelligence about the professionalism and the work of the Bulgarian intelligence. He pays special attention to the work of the Bulgarian intelligence in Austria and to the Bulgarian mentality and psyche through the eyes of the intelligence officer. The author tells about many cases with Bulgarian intelligence in Bulgaria and abroad, including Ivan-Assen Georgiev, the assassination attempt on the Pope and the case of Sergei Antonov, Radio Free Europe, the case of Vladimir Kostov, the "revival process" and many others, not so popular , but their successes and failures are extremely interesting. It complements the detailed exposition with the fun moments and humor of the scouts.