The four papers contained in this volume were presented at the August 1994 meetings of the American Statistical Association as a session titled, "Public Policy and Data Comparability: New Interest in Public Library Data." The first paper, "Public Library Statistics: Two Systems Compared" (Mary Jo Lynch), describes two systems that collect data on public libraries. The Federal-State Cooperative System for Public Library Data (FSCS) is part of the National Center for Education Statistics (NCES) and is the most comprehensive data system. The Public Library Data Service (PLDS) is part of the Public Library Association (PLA), one of the specialized divisions of the American Library Association. The second paper, "Counting Public Libraries in the United States" (E. Walter Terrie), looks at what a public library is, explores issues surrounding determining the actual number of public libraries by type during FY 1992, and includes maps of the United States showing distribution of libraries and library services. The third paper, "A Study in Library Structure and Organization and Their Relationship to the Census of Governments" (Stephen D. Owens), concludes with recommendations for easing the problems of identification, classification, and consistency that are inherent with the collection and reporting of library statistics. The final paper, "Evaluating Coverage in the Public Library Statistics Program" (David Kellerman), addresses two general questions: (1) Given the definition of public libraries, how accurate is the coverage in the Public Library Statistics; and (2) How many libraries exist, but fall outside the scope of the definition and are therefore excluded from coverage? (SWC)