A professional who conducts research to authenticate details, such as customs, costumes, manners of speech, architectural styles, modes of transportation, and other items peculiar to given historical period or specific locality, to avoid anachronisms and inaccuracies in presentation of stage or radio dramas or motion pictures. Reads written historical texts and documents and pictorial material in libraries and museums, consults experts or witnesses of historical events, and visits and observes peculiarities of areas to be used as locale of drama to procure information.