This contributed volume provides a comprehensive understanding of synthetic protocols, characterization techniques, and current applications of iron oxide-based nanocomposite and nanoenzyme materials. It covers basic concepts and recent advancements in iron oxide-based nanocomposites and nanoenzymes, focusing on their synthesis, characterization, and functionalization for specific research applications. The different chapters in the book highlight key characterization techniques including Fourier Transform Infrared Spectroscopy, X-ray diffraction, Scanning Electron Microscopy, and Transmission Electron Microscopy, among others while it also explores various applications of these materials, such as adsorption of heavy metals and dyes, gas sensors, biomedical applications, photo-catalysis, and photovoltaic sensors. This book serves as a valuable resource for researchers and graduate students working in the fields of materials science, chemistry, physics, and biotechnology.