With the revolutionary potential to enhance material properties across multiple industries, clay nanoparticles, often known as nanoclays, have become indispensable additives in polymeric materials. Nevertheless, several challenges are associated with using nanoclays, which have been presented here. This book started by investigating nanoclays and further examining the structural and property differences between natural and synthetic clays. The following chapters looked at polymer–clay (nano)composites and their improved features in paints, coatings, and catalyst support for eco-friendly water filtration and developments in the construction and oil and gas industries. Further prospects were found in using nanoclay particles in cosmetics, biomedical, batteries, and sensors. The text also expanded the conversations about other off-Earth uses of clays alongside their functions as Flame Retardants. Lastly, the book also reviewed the modeling of fire resistance and crystallization behaviors in nanoclay-enhanced polymer composites to paint a clear picture of today’s and tomorrow’s research in this evolving area.