Twelve papers from the Twelfth Annual Clinic on Library Applications of Data Processing are presented here. Following an introductory paper are two articles on data bases and information sources. The fourth article discusses computer-aided information retrieval in an industrial library. Bibliographic searches is the topic of the fifth article, and it is followed by an introduction to NASIC and information services. Experiments in information retrieval for public libraries and information centers are the subjects of the seventh and eighth articles. The ninth article presents a report on machine-readable data bases in Australia. Computer-assisted instruction in libraries and natural language answering systems are the subjects of the tenth and eleventh articles. The last article is a critique of information services. (CH)