"Illinois Libraries" for June, 1975, is devoted to interlibrary cooperation and the multitype library network as exemplified by the Illinois Library and Information Network (ILLINET). The history, geographical coverage, member and affiliate libraries, and the workings of the network at various levels are described. A second section describes the integration of academic, special, and school libraries, along with special resource centers, into a multitype library network. Further activities of ILLINET are outlined in the third section: the purchase of new, non-duplicate materials; staff training for improved reference service; improvement of communications by developing procedures, meetings, workshops, and a newsletter; provisions for evaluating ILLINET; encouraging and providing guidelines for interlibrary cooperation projects. The fourth section covers future developments and planning (such as funding the regional multitype library coordinating councils and computer assisted projects) as well as discussions held in January, 1975, on systems as multitype library agencies. Lists of both the school and academic advisory committee members are provided, along with lists of school, academic, and special libraries participating in ILLINET. (LS)