This guide discusses the best practices for government agencies and non-profit organizations regarding risk and crisis communication. "Sources of best practices should be selected based on an organization or agency's goals. Risk and crisis events are dynamic; therefore, messaging needs to be adapted and updated as the situation changes or worsens. The local context of a risk may require modifying strategies, even if they are based on excellent general principles of risk and crisis communication. In addition, sources may not consistently prioritize best practices in the same way; therefore, several complementary sources should be used. The guide is divided into five chapters: Introduction; Risk Domains; Specific Populations; Social Media; and Additional Resources. Each chapter is divided into categories that list resources specific to that category."