This publication is the first in-depth study of the Belgian military court during World War I. Martial law application and procedures are described in detail and evaluated on the basis of a comprehensive study of previously unexamined archive documents from the Attorney General's Office and the Military Court, including more than 300 Attorney General's circulars, about 5,500 judgments and nearly 1,000 Military Court cases. Criminal procedure, from inquiry to execution, is fully explained through statutes, jurisprudence, circulars and a large number of scientific publications. Martial law practice and its significance for the soldiers are briefly presented and analysed through a number of key questions addressing the language issue and social relations in the army, but also the legal impact of the war, the roles played by military authorities, the relationship between armed forces, etc. This volume contains an enlightening study for all those who want an insight into the prosecution of the military law crimes during World War I.