Since the publication of the first volume of Contemporary Developments and Perspectives in International Health Security, a lot has happened in this rapidly evolving area. Perhaps the most dominant global event of the past eighteen months is the COVID-19 pandemic. Within this general context, the importance of the multiple and diverse international health security (IHS) subdomains is becoming evident, especially when one begins to appreciate the interconnectedness of the modern world and the interdependence of various existing societal systems. Moreover, this complexity presents our civilization with both dangers and opportunities, and among the most pronounced opportunities is our ability to effectively “work together and coordinate” as humanity. With a goal to summarize and synthesize our collective experiences from the COVID-19 pandemic, this second tome of Contemporary Developments and Perspectives in International Health Security is a repository of knowledge and a practical resource for those who seek to learn about the current pandemic as well as for those who may already be preparing for the “next pandemic” or as yet unforeseen IHS threats. In addition to the COVID-19 global response, topics discussed in this book include climate change, mental health, supply chain management, and clinical diagnostics, among others.