Fusion Neutronics Introduction Part I Neutronic Theories and Methodologies for Fusion Neutron Transport Theory and Simulation Neutron induced Transmutation and Activation Neutron Irradiation and Material Damage Radiation Dosimetry and Biological Safety Fusion Nuclear Data Libraries Comprehensive Neutronic Simulation Part II Fusion Neutronic Design Principles Neutronic Design of Fusion Experimental Reactors Neutronic Design Principles for DEMO Reactors and Fusion Power Reactors Neutronic Design Principles for Fusion Fission Hybrid Reactors Part III Fusion Neutronic Experimental Technologies Experimental Methods of Fusion Neutronics Fusion Neutronic Experimental Facilities Fusion Neutronic Experiments. This book provides a systematic and comprehensive introduction to fusion neutronics covering all key topics from the fundamental theories and methodologies as well as a wide range of fusion system designs and experiments. It is the first ever book focusing on the subject of fusion neutronics research. Compared with other nuclear devices such as fission reactors and accelerators fusion systems are normally characterized by their complex geometry and nuclear physics which entail new challenges for neutronics such as complicated modeling deep penetration low simulation efficiency multi physics coupling etc. The book focuses on the neutronics characteristics of fusion systems and introduces a series of theories and methodologies that were developed to address the challenges of fusion neutronics and which have since been widely applied all over the world. Further it introduces readers to neutronics design’s unique principles and procedures experimental methodologies and technologies for fusion systems. The book not only highlights the latest advances and trends in the field but also draws on the lessons learned in the author’s more than 40 years of research. To make it more accessible and enhance its practical value various representative examples are included to illustrate the application and efficiency of the methods designs and experimental techniques discussed.