The author investigates into the dedicatory inscriptions in the book collection of Genrikh (Henry) Trofimenko (1929–2005) – prominent historian, specialist in the US military doctrine. The study expands our understanding of inscriptions as a source of information on the professional environment, its specifics, statuses and relationships of players. The theoretical basis of the study is the provisions that consider the inscription as a historical, cultural and sociocultural phenomenon that reflects both personal and public relations. The main research methods are the structural and content analysis of dedicatory inscriptions and the analysis of open biographical data about their authors and addressee. It is shown that the features of the professional environment are revealed in the inscriptions through: 1) its complex structure; 2) references to the subject of professional discussion or the content of the presented book; 3) indications of the date and place of a specific event or circumstances. The analysis of the institutional affiliation of the authors evidences that the members of Trofimenko’s professional environment were highly qualified professionals who headed and represented government, business and public institutions. G. A. Trofimenko’s involvement in this environment and scientific collaboration with foreign colleagues testify to his high expertise and authority.