Reactor physics is the discipline devoted to the study of interactions between neutrons and matter in a nuclear reactor. This third edition of Applied Reactor Physics, addresses the fundamentals of reactor physics. Legacy numerical techniques are introduced with sufficient details to help readers implement them in Matlab. The fundamental approaches presented here provide a solid foundation for the more advanced and proprietary techniques that readers may encounter in production environments. Applied Reactor Physics emphasizes the algorithmic nature of the numerical solution techniques used in reactor physics. Many numerical solution approaches described in the book are accompanied by Matlab scripts, and readers are encouraged to write short Matlab scripts of their own in order to solve the end-of-chapter exercises. The third edition includes key improvements in the text, a completely rewritten appendix on numerical methods, new end-of-chapter exercises, and an extended bibliography. This book is intended for graduate-level readers who have no existing knowledge of reactor physics. It was initially written as support for graduate-level courses offered in the regular program of the Institut de génie nucléaire (nuclear engineering institute) at Polytechnique Montréal. The book contains sufficient material for an instructor to build three or four graduate courses based on its content.