Many of the world's 40,000 International NGOs (INGOs) work in places where terrorist financing, sanctions breaches, and diversion are key risks. Almost all of the top ten recipient countries of humanitarian aid alone in 2015 were high-risk jurisdictions, for example, receiving more than £7bn between them. When they feel safe to speak, sector workers share sobering stories about what might have happened to some of this money. As INGOs struggle to keep up with worsening humanitarian needs, diversion risks and their complexity remain daunting. The demands of internal stakeholders, donors, banks, and regulators are diverse and even contradictory. Public scrutiny has magnified, but is not always well-informed. Institutional donors transfer ever more risk to implementing partners, while some banks seek to avoid this business altogether, pushing some NGOs outside the global banking system. Looming over all of these converging pressures is a latticework of austere international sanctions and counter-terror regimes. It is no surprise that INGOs find themselves struggling to reconcile this complex set of expectations with their charitable missions. Yet the consequences of failing to do so can be severe; future funding is contingent on reputation, and serious offences litter the regulatory landscape. The implications of breaches can be existential for organisations and criminal for individuals. Terrorist Diversion: A Guide to Prevention and Detection for NGOs is an accessible, pragmatic guide for international NGOs of all shapes and sizes. Clearly explaining the nature of the challenge, and setting out a programme to meet it, it explores how it is possible for INGOs to manage these risks more effectively through their missions - not in spite of them.