In this book, many aspects of the insulation materials have been clarified in certain applications: thermal, acoustic, waterproofing, fireproofing, radiation shielding and electrical insulation. The book holds practical experiences as well as mathematical relations that telling us where technically and economically the effective variables are feasible and controlling the design parameters. The main goal is conserving energy by reducing heat loss or gain, controlling the sounds and offering comfort living as well as saving facilities for long time.