Early modern Europe was a hotbed of espionage, where spies, spy-catchers, and conspirators pitted their wits against each other in deadly games of hide and seek. Theirs was a dangerous trade – only those who mastered the latest techniques would survive. In this engaging, accessible account, Nadine Akkerman and Pete Langman explore the methods spies actually used in the period, including disguises, invisible inks, and even poisons. Drawing on a vast array of archival sources, they show how understanding the tricks and tools of espionage allows us to re-imagine well-known stories such as the Babington and Gunpowder plots.