In this monograph, the reader is offered an analysis of the Russian direction of foreign policy by Otto von Bismarck on the eve and during the unification of Germany, one of the key periods of German history of the 19th century. The work covers a 20-year period of European history: from 1851, when Bismarck was appointed to his first diplomatic post in Frankfurt, to 1871, when the German Empire was proclaimed. This study was carried out on the basis of a comprehensive analysis, first of all, of a wide range of materials stored in the archives of Germany and Russia, collections of documents, influential and authoritative Russian and German daily periodicals of that time, sources of personal origin. A joint study of these materials on this topic has not previously been conducted. Most of the documents are being introduced into scientific circulation for the first time. The study of this complex topic contributes to a better understanding of the history of relations between the German states and the Russian Empire in the XIX century. and the role that Russia played in the complex process of German unification.