The results of the second 18 months (December 15, 1968-June 30, 1970) of effort toward developing an Information Processing Laboratory for research and education in library science is reported in six volumes. This volume contains: the rationale and description, definitions, index and coding key, retrieval procedures, and examples. This manual is intended as an explication of the REFSEARCH system as implemented in the Information Processing Laboratory. Part II of the manual gives the rationale of the REFSEARCH system. Part III defines the terms used in "REFSEARCH language." Examples are given in Part VI to show how "handles" are identified and converted into channel entry terms, and how other elements of a search specification are assembled. (Other volumes of this report are available as LI 003607, LI 003608, LI 003610 and LI 003611). (Author/NH)