Nanotechnology and nanoscience are the study of extremely small things. The study is based on objects within the nanoscale size as well as the 'bottom up' principle.
Nanotechnology was originally brought to light by the studies of physicist Richard Feynman at the California Institute of Technology in December of 1959. Feynman's talk entitled "There's Plenty of Room at the Bottom" described a process where scientists would manipulate and control individual atoms and molecules.
Nanotechnology began in earnest with the invention and application of the scanning tunneling microscope, or STM, and the atomic force microscope, or AFM. The advancement of precision and understandings of coding are the basis for all Nanotechnology.
As for the modern applications available, Mihail Roco of the U.S National Nanotechnology Initiative has described four generations of development: passive nanostructures, active nanostructures, systems of nanostructures and molecular nanosystems.
Currently Nanotechnology is in the first generation with materials designed to do a single task. Aerosols and colloids are used in dispersed and contact nanostructures. Incorporating nanostructures include coatings, reinforced composites, polymers, ceramics and nanostructured metals. With this broad an application of nanotechnology, there are thousands of companies currently using the technology to alter their products on a nanoscale.