A tool for practitioners and policy-makers to get up to speed quickly with the fundamentals of security sector reform (SSR). The SSR Backgrounders are an accessible, concise, “first stop” resource for readers seeking to understand but also to critically assess current approaches to good SSG and SSR. Each SSR Backgrounder introduces a topic or concept summarizing current debates, explaining key terms and exposing central tensions based on a broad range of international experiences. The SSR Backgrounders do not promote specific models, policies or proposals for good governance or reform but do provide links to further resources that will allow readers to extend their knowledge on each topic.