War is a drug. It is a hard drug, but it is not prescribed by doctors. It kills, and when it’s gone, the person who gets it goes into withdrawal. And such people are tossed between a boring peaceful life and war, which gives this life flavor. After all, every day spent in war is worth several in civilian life, especially if you fight in a PMC! Few people know that PMCs have existed as long as wars have existed. From ancient times to the present day. This publication covers the history and evolution of mercenary armies. The military skill of private armies has been valued from time immemorial. Greek warriors in the service of the ancient Persian monarchy; the stern Varangian guards who guarded the Byzantine emperors; medieval Italian condottieri, who took and surrendered cities; German landsknechts of the Reformation era, assembled into dashing troops. Matching them are the “soldiers of fortune” of the 20th century, who participated in the invisible war of the superpowers - the USA and the USSR, as well as the warriors of Modern Times, united in private military companies - PMCs, which now have units of all branches of the military. For centuries, interest in the warrior profession does not fade, and the ranks of PMCs around the world are regularly replenished. Why is this happening? In this book the reader will find the answer to this and other questions.