The Flow System provides descriptions and characteristics of the different methods, techniques, and tools. It shows how to generate and nurture self-organizing teams that mobilize the full talents of those doing the work to cope with dizzying change and complexity, while also drawing on the contributions of those for whom the work is being done–the customers. The book is a compilation of years of research from the fields of complexity, leadership, organization theory, psychology, and team science. It draws on authors years of experiences in the disciplines of engineering, military safety, and strategy throughout various organizations involved in implementing and practicing agile and lean methodologies. Also, in light of the COVID-19 outbreak, which is causing a complex environment to emerge around the globe, a preface and forwards were provided to position The Flow System within the current complex environment, in which we will be living moving forward.