This book is dedicated to Grand Duke Nikolai Nikolaevich the Younger (1856–1929), uncle of the last Russian Emperor Nicholas II. Nikolai Nikolaevich was inspector general of cavalry for 10 years and did a lot to improve this type of troops. In addition, he served as commander-in-chief of the guard troops and the St. Petersburg Military District. Nikolai Nikolaevich was the Supreme Commander-in-Chief of the Russian Army in the initial period of the First World War (until August 1915), and then - until the February Revolution - the Commander-in-Chief of the Caucasian Separate Army. Many representatives of Russian society considered the Grand Duke a possible leader in the process of strengthening Russian statehood. Nikolai Nikolayevich did not play this role, but still went down in Russian history as an outstanding and talented figure of a tragic era. The book was first published by the Parisian publishing house “Imprimerie de Navarre” in 1930.