Book excerpt: Nanomaterials and nanocomposite materials have been developed as corrosion inhibitors and are the most noble and effective alternatives to traditional organic corrosion inhibitors. Nanomaterials provide reasonably high anticorrosive activity in both aqueous and solution phases. A unified approach to this task is lacking, however, which highlights the role of all disciplines involved in the creation and use of corrosion protection coatings for metals. Fouling is the process of accumulating unwanted material that is mostly non-living and comprised of detritus and organic or inorganic compounds, or organisms, such as tiny viruses up to giant kelps. This book covers both the processes of biofouling and anti(bio)fouling, and the devices that stop the biofouling process. This book provides a missing synopsis by providing an understanding of the anticorrosive and anti-biofouling effects of nanomaterials and nanocomposites under different environments. It features an up-to-date picture of the quality and chemistry of a substrate surface, its proper preparation by conversion treatment, the function of resins and anticorrosive pigments in paints, and novel concepts for corrosion protection.