Making polymers into nanoparticles as an essential step in polymer solution processing is of key importance for many applications of polymers. This book seeks to uncover the basics and recent advances in polymer nanoparticles, including polymer synthesis, self-assembly, properties, and applications. It encompasses the various preparation methods of polymer nanoparticles, broadly ranged from single chain collapse to polymerization methods and solution self-assembly. It showcases a wide range of advanced applications of polymer nanoparticles in several fields that include pharmaceutics (drug and nucleotide delivery), biomedicals (bioimaging, diagnosis, and therapeutics), energy (batteries and solar cells) and environmental (catalysis and water purification). This book is enriched with a comprehensive range of content, incorporating synthesis, properties and applications in polymeric nanoparticles that will serve as a suitable beginner guide and survey book in polymer nanomaterials, as well as a useful tool for graduate students, scientists and practitioners in related fields or industries such as chemistry, materials science and engineering, nanomaterials, energy storage and conversion devices, and biomedicine.