In the sixteenth century, espionage acquired new methods compared to the past and, thanks to the development of diplomacy and the postal service, which facilitated the transmission of information. European sovereigns now had up-to-date means to discover the intentions of the enemy. In this way, the profile of the new "spy" was defined: a specialized agent who knew cryptography and secret codes, as well as knowing how to identify the fastest and most effective routes to send dispatches. The protagonist of this book research was Naples, where the court promoted the creation of a defensive system and a well-structured espionage "network". In the strategy of the Habsburgs, in fact, espionage represented a confidential look at the Barbary Turks and an essential tool in the conflict with the Ottoman Empire.