The advent of X-ray Computed Tomography (CT) as a tool for the soil sciences almost 40 years ago has revolutionised the field. Soil is the fragile, thin layer of material that exists above earth's geological substrates upon which so much of life on earth depends. However a major limitation to our understanding of how soils behave and function is due to its complex, opaque structure that hinders our ability to assess its porous architecture without disturbance. X-ray imagery has facilitated the ability to truly observe soil as it exists in three dimensions and across contrasting spatial and temporal scales in the field in an undisturbed fashion. This book gives a comprehensive overview of the "state of the art" in a variety of application areas where this type of imaging is used, including soil water physics and hydrology, agronomic management of soils, and soil-plant-microbe interactions. It provides the necessary details for entry level readers in the crucial areas of sample preparation, scanner optimisation and image processing and analysis. Drawing on experts across the globe, from both academia and industry, the book covers the necessary "dos and don'ts", but also offers insights into the future of both technology and science. The wider application of the book is provided by dedicated chapters on how the data from such imagery can be incorporated into models and how the technology can be interfaced with other relevant technical applications. The book ends with a future outlook from the four editors, each of whom has over 20 years of experience in the application of X-ray CT to soil science.