Polymer dielectric films, ranging in thickness from less than 100 A to several microns, have become increasingly useful for basic investigations of surface phenomena and thin film electrical conductivity and for thin film electronic device and circuit development. The preparation and characterizing properties of thin polymer films are discussed with particular emphasis on recent developments in such areasa s ultraviolet surface photolysis, electron bombardment, gaseous electrical discharge, and special chemical processes. Previously unpublished data on certain aspects of polymer dielectric films are presented, and present and potential applications are briefly reviewed.