A nanobarcode is a nanoscale label or marker used to encode and track information at the molecular or cellular level. These tiny barcodes are typically made from nanoparticles or nanostructures, and they utilize unique physical, chemical, and optical properties to store information. Nanobarcodes have become increasingly significant in biotechnology, medicine, and materials science due to their ability to label, track, and identify objects or substances at extremely small scales. This book will give a comprehensive description on the materials composition, encoding methods, detection system.