The field on nanotechnology is still in its infancy but continues to progress at a much faster rate that any other field. Many methods to synthesize nano particles, disperse them in a carrying fluid to form a composite and exploit its extraordinary properties is the goal and dream of many researchers engaged in this field. It is not possible to cover every nano particulate matter and its role in materials revolution. The approach adopted here was to focus on carbon nanotubes and nano clays and explore their importance and their role in composites. Hence the chapters presented in this book address processing, rheology, mechanical properties and their interaction with fiber composites. Thus, this book is a collection of nine chapters written by researchers who are at the forefront of their field which address the role of nano particles in composites.