This book provides detailed information related to nanofluids, synthesis and preparation, morphologies of nanoparticles, selection of base fluids and thermophysical properties of nanofluids. The advantage of various conduits, the improvement of the heat transfer performance of phase change materials (PCMs), and the base PCMs for diverse applications are also discussed. Crucial difficulties like stability, aggregation, and clogging of nanoparticles are detailed including factors like the size, shape, and motion of nanoparticles that influence the heat transfer performance of nanofluids. Challenges, applications, and scope of the future works in the subject area are included. Features: Covers heat transfer techniques in utilization of base fluids application of phase change materials (PCMs) Describes preparation and characterization of nanofluids and nano-based PCMs Explains how nanoscience can be utilized in heat transfer studies Reviews conventional heat transfer fluids This volume is aimed at graduate students and researchers in thermal engineering, heat transfer, material science and engineering, and heat transfer enhancement.