This handbook has evolved from the authors' teaching and research experience in the field of nanoparticle biosensing. It encompasses protocols for synthesis of various forms of metal oxide nanoparticles; study of the various characterizing techniques that help deduce the shape, size, and morphology of these nanoparticles; and applications of these nanoparticles in the field of biosensors. It aims to introduce the various basic principles and practical information needed by undergraduate and advanced-level students and researchers to understand the science behind nanoscale sensing.