This French-language study examines the ninja, the covert warriors associated with Japan’s feudal past. Drawing on the title’s reference to “samouraïs de l’ombre,” the book places ninja in the broader context of Japanese military culture, samurai society, espionage, and martial tradition. It is aimed at readers interested in the historical roots of ninja practices, their role in conflict and intelligence gathering, and the legends that have shaped their modern image. Rather than treating the subject as pure myth, the work presents ninja as part of Japan’s martial and social history, exploring how secrecy, strategy, and specialized training contributed to their enduring reputation. The volume is suitable for general readers seeking an accessible introduction to ninja history and to the cultural world from which these figures emerged.