The First World War is a tragic turning point in the history of the entire European civilization, marking the beginning of the 20th century, which entailed revolutionary upheavals and mass terror. The map of Europe was completely redrawn; The most powerful empires in the world collapsed. In their place new states arose, the contradictions between which made a new world war inevitable. What do we know about the First World War? Hundreds of volumes published in Soviet times told us about it exclusively from “Marxist-Leninist” positions. The monarchy that waged this war collapsed, and its most radical opponents came to power, striving to erase from history everything that was connected with the “damned tsarism.” But still, it cannot be denied that it was the First World War that became a war of a “new” type: both in terms of the scale of the states involved in it, and in terms of the size of the operating armies, and in terms of losses. On the pages of this book, both the most tragic pages of the Great War and the most striking and undeservedly forgotten events of 1914–1918 come to life. All this makes the First World War truly the most mysterious war in the history of our Fatherland.