The activities of the Information and Documentation Center (IDC) at the Royal Institute of Technology in Stockholm, Sweden are presented in this annual report for the fiscal year 1972-1973. The IDC is a research project on computer-based information retrieval funded by the Swedish Council for Scientific Information and Documentation and the Office of the Chancellor of the Swedish Universities. Several important changes in equipment occurred in 1972-73. A new computer configuration became operational; new software was implemented; and an on-line connection with the European Space Research Organization was installed. One of the major activities reported on is the initiation of a large scale project on information need in the social sciences. Statistics on searches, search profiles, users, and data bases are given. Also included is information on user education programs, contacts with external organizations and with the public, participation in meetings and other activities, and a list of staff publications. (JG)