This book presents nanoparticles as potential drug delivery carriers for overcoming the blood-brain barrier. The initial chapter of the book discusses complex brain disorders, the currently available therapies, and their limitations. The book discusses the potential applications of polymeric nanoparticles, lipid nanocarriers, liposomes, inorganic nanoparticles, dendrimers, and stimuli-responsive polymers for targeted brain drug delivery. Further, it evaluates the development and role of different cell lines and animal models in brain research. Towards the end, the book reviews challenges, safety, toxicity, regulatory aspects, future possibilities, and constraints in the clinical translation of nanocarrier systems to treat neurological disorders. The book as such provides valuable information to neuroscientists, and researchers working in pharmaceuticals, nanomedicine, drug delivery research, and nanotechnology.