Book excerpt: This book highlights the significance and usefulness of nanomaterials for the development of sensing devices and their real-life applications. The book also addresses various means of synthesizing functional materials, e.g., hydrothermal deposition process, electrospinning, Ostwald ripening, sputtering heterogeneous deposition, liquid-phase preparation, the vapor deposition approach, and aerosol flame synthesis. It presents an informative overview of the role of functional materials in the development of advanced sensor devices at the nanoscale and discusses the applications of functional materials in different forms prepared by diverse techniques in the field of optoelectronics and biomedical devices. Major features, such as type of advanced functional, fabrication methods, applications, tasks, benefits and restrictions, and saleable features, are presented in this book. Advanced functional materials for sensing have much wider applications and have an enormous impact on our environment.