The sol-gel method is a powerful and versatile wet chemical process for synthesizing advanced materials, particularly oxide-based nanostructures. Its ability to produce materials in various forms, such as powders, thin films, fibers, and aerogels, makes it a valuable tool in fields ranging from electronics and energy to medicine and environmental science. This book provides a comprehensive overview of sol-gel technology, highlighting its cost-effectiveness, flexibility, and precise control over material properties. Special attention is given to developing sustainable sol-gel processes in response to increasing environmental concerns.