Configuration is the glue for logically integrating cyber infrastructure components to satisfy end-to-end requirements on security and functionality. Every component has a finite number of configuration variables that are set to definite values. It is well-documented that configuration errors are responsible for 50%-80% of infrastructure vulnerabilities and downtime and it can take months to set up and adapt infrastructure. This is because the large conceptual gap between requirement and configuration is manually bridged. This talk presents a Science of Configuration to automatically bridge this gap. The Science is embodied in the Distributed Assured and Dynamic Configuration (DADC) suite of tools for requirement specification, configuration synthesis, repair, vendor-specific adaptation, visualization, emulation, verification, distributed configuration, in-band configuration, reconfiguration planning and moving-target defense. DADC leverages modern SMT solvers that can solve a million constraints in a million variables in seconds, and group communication protocols that provide total-ordering message delivery guarantees. We will sketch a new application of DADC to cloud configuration.