This book describes all the techniques and procedures required for designing and constructing a repository for hazardous waste and for assessing its function in short- and long-term perspectives. It provides new aspects on disposal of such waste, especially HLW, by making it clear that, in contrast to the common belief that the rock itself it an effective barrier to the transport of contaminants like radionuclides, tectonics and long-term changes in the rock structure will make it serve only as a 'mechanical support to the chemical apparatus', while effective retention of the hazardous elements is solely provided by properly designed and manufactured containers ('canisters'). This brings the longevity of the containers in to focus, which in turn, requires that all degrading physics/chemical processes are considered. This occupies a considerable part of the book.