This product is comprised of the source code for both the online retrieval software and the data base processing and generation software for many of the NIH/EPA CIS (Chemical Information System) components. Software for the CIS Chemical Registry System is also included. All of the retrieval software has been operational on a DECsystem-20 computer facility under the TOPS-20 operating system; the source code for this software is included on a single reel of magnetic tape. For some of the CIS components, the data base processing and generation software is, however, operational on a large scale IBM 370 computer facility. The source code for this software is included on a second reel of magnetic tape. Source code for the following CIS components are included on these files; a directory for each of the tapes is available as supplementary documentation...Software Description: The system implementation is divided between a DEC system-20 operating under TOPS-20 and an IBM 370/168 operating under OS/MVS. The source code is both Fortran and Assembly language.