User experiments are the main theme of this tenth issue in the series of Project Intrex semiannual activity reports. This system is undergoing tests with users who are motivated by their need for information rather than an interest in the machinery by which it is stored, retrieved and presented. Test results will indicate which fields in the augmented catalog are most helpful to the user, which of the retrieval program features are most effective and which display techniques are most congenial in continued use. This kind of information will make it possible to design the future information systems in which libraries and information centers will utilize the new computer-communications technology. The seven major sections of the report are: (1) introduction, (2) research and development activities, (3) model library, (4) Project Intrex staff, (5) current publications, (6) past publications 1969-1970, and (7) past publications 1966-1969. The research and development activities section covers: (1) status of the program, (2) user experiments, (3) augmented-catalog inputting, (4) storage and retrieval, (5) display consoles, and (6) full-text storage and retrieval. The model library section includes: (1) status of the project, (2) point-of-use instruction, and (3) library pathfinders. (NH)