Illegal intelligence officers are the golden fund of foreign intelligence. They take years to prepare. And they are trained for very complex, responsible work abroad. In the history of Soviet and Russian intelligence, intelligence officers are known who were ambassadors of foreign countries, businessmen, gangsters, and simply street sellers... Until recently, it was believed that intelligence was the most closed area of human activity. But today this concept has changed to a large extent. Many books have appeared about intelligence work, especially in the pre-war and war years. Films and TV series have been made about her. This book tells about outstanding Soviet illegal intelligence officers who worked in Western Europe and South America from the 1920s to the 1950s. The reader will learn about Y. Serebryansky, A. Korotkov, D. Bystroletov, I. Grigulevich, L. Trepper and other soldiers of the invisible front.