According to conventional wisdom, systematized intelligence and espionage are ‘modern’ phenomena. This book overturns this academic orthodoxy, recounting the arresting story of the world’s earliest centrally organized state intelligence organization, created in Renaissance Venice. Headed by the infamous Council of Ten, Renaissance Venice’s intelligence service resembled a public sector institution that operated with remarkable corporate-like complexity and maturity, serving prominent intelligence functions, which included operations (intelligence and covert action), analysis, cryptography, steganography, cryptanalysis, and even the development of lethal substances such as poison. The book details Renaissance Venice’s systematic attempts to organize and manage a central intelligence service made up of innumerable state servants, official informants, and amateur spies, who, dispatched across Europe, Anatolia, and Northern Africa, conducted Venice’s stealthy intelligence operations. Exploring secrecy as a vehicle of knowledge exchange that fostered identities, alliances, and divisions, the book also reveals Venice’s fabled department of professional cryptology, and recounts some of the extraordinary measures deployed by the Venetian authorities in their ongoing effort to maintain the security of the Venetian state. These included tortures, assassinations, and chemical warfare. Overall, the book not only reveals a plethora of secrets, their keepers, and their seekers but explores the social and managerial processes that enabled their existence and furnished the foundation for an extraordinary intelligence organization. For this reason, Renaissance Venice’s central intelligence apparatus is explored and analysed as an organization rather than as the capricious intelligence enterprise of a group of state dignitaries, as was the case for other Italian and European states.