This book manuscript focuses on police surveillance of people deemed “suspicious persons” by the French colonial administration of French West Africa (Afrique Occidentale Française—AOF) in the interwar period. Police surveillance of “suspicious persons” emerged as an interwar phenomenon following a policy created during the First World War to monitor foreigners, but became an important strategy of the Colonial Ministry in Paris and the administration of French West Africa in the 1920’s. The book traces both the emergence of the concept of “suspicion” at an empire-wide level and the implementation of surveillance practices in local contexts. The book covers the history of the French administration and the lives of “suspects” in order to understand both state and society in French colonial Africa. It reveals the paranoia and limits of state power, but also slices of life and the rich diversity of people that emerged in interwar colonial Africa.