This paper focuses on issues in the relat~onshlp of library and information science with a closely allied chsciphne, communication studies. It is obvious that researchers in both fields study topics similar in focus, such as information theory, information-seeking behavior includ~ng user studies, systems theory, invisible colleges, the diffusion of knowledge, human interaction with information /communication technologies and the information society. In order to discuss the comparison of theoretical <and research perspectives of the two, this paper suggests several models, and d~scusses the nature of the evidence necessary to validate each.