Starting from two newly published theses on Swedish rock engravings, methods and principles for documentation of this special kind of ancient monument are discussed. The main principle of documentation is the retrieval of knowledge. It is recommended that the registration of rock engravings, in association with that of other ancient monuments, be made at three levels: localities, areas of engraving, and single figures. A research critical review of the methods of reproduction prompts the conclusion that every method involves subjective elements. Perhaps a contour drawing gives the most reliable picture. It is advisable that every documentation primarily contain a verbal description of special standards, irrespective of the methods of reproduction. The statements are exemplified by the documentation of the rock engravings of Östra Eneby parish, province of Östergötland. -- AATA