Geotechnical engineering, civil engineering, and other allied engineering disciplines have, for a long time, shifted from problem solving to creating problems that plague our planet. This book, Sustainable Soils Re-Engineering, is here to point the world to a more environmentally friendly approach to solving problems using engineering skills. This book moved from the use of cement, which contribute hugely to global warming through the release of oxides of carbon, to the utilization of derivatives of solid-waste materials in the form of ash or powder. These are derived through direct combustion and crushing. Yet one may wonder where the oxides of carbon released during combustion is managed. This book also proposes a model through which oxides of carbon are entrapped through a controlled combustion mechanism. That way, ash is generated for use as geomaterial, and the environment is left healthy. The operation of utilizing solid waste equally rids the environment of its plaguing condition in the process. Also the more practical approach exposed in this book will assist researchers across the world to explore new and novel grounds toward helping humanity. More on this is the bringing forth of mathematical methods like the extreme vertex design adopted in modeling properties of re-engineered soils.