Certain wastes such as nuclear wastes, are so hazardous that their disposal creates a major challenge requiring considerable technical skill and understanding. Their effective isolation in the ground depends on the properties of the surrounding clays. This authoritative book explains the detailed function of clay-based engineered barriers, gives a number of examples of the design and construction of successful sites, and sets out conceptual and theoretical models for the prediction of their performance. It begins by providing a scientific grounding in the relevant aspects of clay science and successively moves onto the practicalities, while retaining the scientific slant. It will be useful for students, and invaluable for research institutes, specialists in environmental protection agencies and consultants in the field of disposal of hazardous waste.