The Psychology of Spies and Spying tells the story of the people involved in spying: the human sources (agents) who betray their country or organisation and the professional intelligence officers who manage the collection and reporting process. It provides a rigorous psychological analysis of the personality and motivation of individuals involved in spying. This book shows the importance of developing trust between agents and handlers, between agencies and their government and ultimately the public. It shows how agent handlers, operating in environments of complete secrecy, need to manage dark side behaviours because agents are selected for their access to secrets, not for their qualities. It explains why motivation is rarely simple since it is invariably a combination of many issues.It explains how fiction writers are good at developing plots and the characterisation of spies, but few capture the motivation of agents well. Finally spy gadgets and techniques are also described in detail. Included are twelve agent case studies in which most were motivated by ideology, had significant misfortune in their youth and offered their services rather than being coerced into betrayal. The Psychology of Spies and Spying promotes the view that in the world of intelligence, it is trust not betrayal which dominates the mindset.