There is an argument that says that research in Public Administration is always about social complexity. This argument is true. There is also an argument that says that Public Administration is actually very little informed by complexity. This is equally true. The differences lie in the different takes on complexity. The latter approach understands that comprehension of complexity requires a specific theoretical framework and associated tools to look into the black box of causality. The authors in this edited volume gathered in Rotterdam (The Netherlands, June 2011) to discuss how the complexity sciences can contribute to pertinent questions in the domains of Public Administration and Public Policy. Their contributions are presented in this edited volume. Each contribution is an attempt to answer the Challenge of Making Public Administration and Complexity Theory work-COMPACT, as the title says. Together, they present an overview of the diverse state of the art in thinking about and research in complex systems in the public domain.