The objective of this book is to provide the engineer with an effective understanding of the composition, mode of formation and architecture of rocks and soils, geological structures and alteration phenomena, as far as they might impinge on the planning, design, mitigation of risks and financial/time constraints of ground engineering projects. Project engineers need to have a sound comprehension of geological models presented to them, in particular their reliability, their limitations and, of vital importance, the assumptions made in their formulation.