Économie de la défense is a French-language nonfiction study of how governments finance, organize, and evaluate defense activity. It examines the relationship between military needs and economic constraints, including public spending, procurement, industrial capacity, manpower, research, and the opportunity costs of security policy. The work frames defense as a field shaped by budgets, institutions, technology, and political priorities, as well as by strategic commitments and public-resource limits. With a concise format, it is suited to readers seeking an introductory but analytical account of defense economics and public-policy decision-making in a modern state. It also points to the wider effects of defense spending on national industry, fiscal planning, employment, and public debates over security commitments.