The book "History of the Great War. Volume III (of 12). The beginning of the war, the invasion of Belgium, the Battle of the Marne" tells about the events of the First World War, which became a crossing point for many countries. The author describes in detail the beginning of the conflict, the invasion of the German army into neutral Belgium, as well as the decisive battle on the Marne River. In the book, the reader will find not only a documentary reproduction of the events, but also an in-depth analysis and comparison of different points of view on the initial stages of the war. The author helps to understand the motivations of the parties to the conflict, their strategies and tactics. This book will be a valuable resource for those interested in the history of warfare, politics, and geopolitics of the early 20th century.