This book provides information for a physicist or radiation effects engineer to obtain a deeper knowledge and understanding of simulating radiation backgrounds, predicting the effects of radiation, and relating all this to tests in irradiation facilities. Starting with a detailed overview of how particles interact with matter. From thermal neutrons all the way up to high energy hadrons in the TeV range as seen in space and accelerator facilities, the book proceeds to discuss in detail the different radiation environments found in the various research fields and industries. Including concepts such as particle flux and particle energy spectra and how these are modelled, which is the starting point and input for the full radiation background simulations. A complete description of how particle transport programs such as FLUKA or GEANT4 are used to simulate the complete radiation environment and provide the radiation quantities of interest that the physicist or engineer can use to predict device or system performance. The core of the book reviews how radiation impacts sensors, electronics, people across various fields. The whole concludes with coverage of mitigating against the effects of radiation and irradiation testing including issues such as dosimetry, in-situ testing, test methods and standards. The reader will benefit from an up to date book and resource covering all aspects of understanding and solving problems related to working in challenging radiation environments. The knowledge gained will allow the reader to manage their own R&D goals related to simulating and testing technologies for applications where radiation is a concern.