A citation analysis was applied to articles published in the Journal of the American Society for Information Science. The bibliographic data encompassed 427 genuine articles from the period 1973-1999. In order to find an intellectual foundation of information retrieval,a co-citation analysis of the most cited works of IR was carried out. In addition, current research themes of information retrieval clusters based on bibliographic coupling were analyzed.The results showed that the field of information retrieval mainly can be divided in two parts; one algorithmic and one user oriented. Essential concepts and research themes and their intertextual relations were identified. The author argues that citation analysis of bibliographical data can be used successfully as a guiding tool when studying a new curriculum or starting a research enterprice.