Predominantly organic wastes can be effectively treated by biological means to yield useful end products like methane gas as fuel and digested slurry as soil conditioner. Inert materials like plastics are effectively blended with other building materials, thereby improving the quality of the finished product and at least partially solving the problem of disposal of plastics. Inorganic wastes are excellent candidates for recovery of reusable building materials like sand and fine aggregate. Recycling of useful components from e-wastes goes a long way in reducing environmental pollution by toxic and hazardous wastes. This book places before the reader different ways and means used by scientists and engineers to minimize pollution of our natural resources and their overexploitation.