Silicon, silica and silicones each have important but separate technological roles to play for mankind in this millennium. All three have the element silicon (Si) in common but they have unique and distinctive chemistries, properties and applications. This book describes recent advances in silicones and the advanced materials which are based on the siloxane bond (Si-O). We have seen tremendous developments in silicon-based materials over the past century and yet clearly there is still much potential for new advanced materials based on the siloaxne bond. With the high abundance of silicon and oxygen on Earth, we are probably working with the most sustainable and green materials if we adopt the correct materials chemistry, materials processing, materials recovery and materials reuse strategies.