This album of photographs of Russian revolutionaries was created by the Russian Imperial Secret Police (Okhrana), Paris office. Photographs were a principal tool used by Okhrana intelligence agents. The Okhrana inserted photographs of important revolutionaries in albums for use as reference and instructional and recognition materials. Pocket-size albums were entrusted to agents assigned to surveillance tasks in the field. Not all of these albums are in the same arrangement of pictures, while the numbering system for persons in the illustrations is usually the same. Thus, the agent reporting from the field did not have to mention the name of his target, but only the number assigned in the album.