The book of academician of the Russian Academy of Natural Sciences V. B. Mironov is dedicated to the First World War, the centenary of which is celebrated in 2014. This is a deep, serious study of who was interested in unleashing this massacre of millions of people, which countries and why participated in it, how events developed and what are the results of the war. The book is based on hundreds of documentary sources, testimonies of witnesses and participants in events, analytical materials of scientists, memoirs of politicians and military figures.