Ink jet printing is the formation of an image by projecting droplets of ink in a controlled fashion onto a receiving surface. The ink can be water-based, solvent-based, or a wax-like material that is applied as a molten liquid. Ink jet print heads are activated by digital electronic signals, tying such printing into computer technology. Paper has an important role in image quality. In color ink jet printing, for example, coated paper is a necessity. Following a listing of the components needed in an ink jet printing system, this paper lists ink jet applications. This is followed by a listing of significant events in the history of ink jet printing from the first practical experiments in 1867 through Kodak's thermal ink jet in 1992. A discussion of ink jet printer market leaders is followed by a review of basic ink jet technologies. Other topics addressed are continuous flow ink jet, thermal ink jet technology, piezoelectric technology, ink jet media, ink jet myths, ink jet engineering, ink quality control, market dynamics, the reasons for refilling ink jet cartridges rather than purchasing new ones, and future developments. 9 figures