Silicone dioxide nanoparticles are essential in the production of composite materials.This book contains an analysis of the properties and methods for producing and using silicon dioxide nanoparticles. They are the basis for many practical applications due to their stability, low toxicity, and ability to functionalize using a few molecules and polymers. Three main processes for producing silicon dioxide nanoparticles are considered: the pyrogenic method, the sol-gel process, and hydrometallurgical methods for processing silicate rocks. The book provides an overview of the latest advances in the production and properties of the polymer and cement-based materials modified with nano-SiO2 in terms of the relationship between these properties and the interaction of the nanosilica with the polymer or cement matrix.