Neutron and synchrotron facilities, which are beyond the scale of the laboratory, and supported on a national level in countries throughout the world. These tools for probing micro- and nano-structure research and on fast dynamics research of atomic location in materials have been key in the development of new polymer-based materials. Different from several existing professional books on neutron science, this book focuses on theory, instrumentation, an applications. The book is divided into five parts: Part 1 describes the underlying theory of neutron scattering. Part 2 describes the various instruments that exist and the various techniques used to achieve neutron scattering or bombardment. Part 3 discusses data treatment and simulation methods as well as how to assess the environment of the sample (temperature, pressure, shear, and external fields). Part 4 addresses the myriad applications of small and large molecules, biomolecules, and gels. Part 5 describes the various global neutron sources that exist and provides an overview of the different reactors.