In recent years, there has been a lot of interest in using nanotechnology in medicine to diagnose and cure various infectious diseases. Although the precise mechanism of action is frequently challenged, many nanosized materials have been extensively explored for this purpose, using their innately unique features. Their functionality has also been enhanced by the addition of various coatings, such as those that increase chemical stability and stealth properties or contain targeting agents that lessen off-target effects while producing effective "smart" nanoplatforms for the early detection, treatment, and possibly resolution of diseases. This book aims to compile research and review articles that concentrate on the synthesis, characterization, and applications of nanomaterials, such as nanoparticles, with a focus on investigating novel ways to improve their properties and create new efficient diagnostic, therapeutic, or theranostic approaches with a clear understanding of how they work.