Risk communication, specifically the development of a multi-hazard, multicultural, and people-centered forecasting and early warning systems, is considered an important and necessary component of resilience building efforts by such recent initiatives as the Sendai Framework, the United Nations International Strategy for Disaster Reduction, and the Rockefeller 100 Resilient Cities, among others. Risk communication, being a dynamic process, requires the exchange of information among stakeholders to aid with preparedness, response, and recovery efforts before, during, and after an extreme event. Social media and other decentralized, collaborative, and network-based systems have become popular platforms for risk communication because they allow emergency management agencies and the public to share information in near real time. Undoubtedly, risk communication is crucial in building resilience and mobilizing the public to take action. This chapter presents an overview of the key concepts discussed in the book.