This is the fourth volume of the handbook of functional nanomaterials (4 volume set). Functional nanomaterials appear in our daily lives. These materials mainly include nanocomposites, nanopowders, nanoparticles and nanocoatings. Nanotechnology enables the creation of structures that do not exist in nature, those which cannot be produced by conventional chemistry. This research aims to create and exploit the structures and systems which involve unique applications due to their small dimensions. The main difference between nanotechnology and other technologies is found within the dimensions and properties of the materials and structures applied to this technology. This volume mainly discusses the properties and commercialisation of functional nanomaterials. Some of the functional nanomaterials that were discussed in this volume are graphene-based nanocomposites, nanoporous materials, ionic liquids-carbon nanotube nanocomposites, carbon nanotube/nanofiber cement-based composites, titania nanostructured materials, nanostructured multi-layer films, ZnO nanostructures, biomolecular nanoconjugates, functionalised magnetic nanoparticles, nano latex materials, semiconductor quantum dots, mesoporous silica-based sensors and keratin nanomaterials. There are 21 chapters in this volume. Each one includes examples of these interesting materials, supported with appropriate figures for better clarification.