Over the past several years, numerous CALS technologies have been developed for improving productivity and the quality of products and services in an organization. Among these technologies, Interactive Electronic Technical Manual(IETM) has been recognized as one of the most important CALS technologies. IETM is a technical manual authored by means of an appropriate media in a digital format. This study was an attempt to establish conceptual foundations in the literature for IETM. This study described the concept of IETM and differentiated IETM from a technical manual. Also, the author suggested an effective approach to developing an ITEM and explained the relationship between HyTime/MID and IETM.