Most researchers, even with computers, find only a fraction of the sources relevant to their interest. As Library of Congress reference librarian Thomas Mann explains, people tend to work within one or another mental framework that limits their basic perception of the universe of knowledge available to them. Some, for example, work within a subject-disciplinary framework which is often defined by a core list of specific reference sources covering a particular subject area. But, Mann points out, while searching within the boundaries of this model allows students and researchers to find many specialized sources, the researchers also become, at the same time, blinded to other possibilities - they do not perceive that works of interest to their own subject appear within the literature of many other disciplines, nor do they perceive any of the ways of searching those other areas. Subject expertise in one field is, in this model, achieved only at the high cost of losing - usually unconsciously - cross-disciplinary breadth of access to much other relevant material. In Library Research Models, Mann examines the several alternative mental models people use to approach the task of research, and demonstrates new, more effective ways of finding information. Drawing on actual examples gleaned from 15 years' experience in helping thousands of researchers, he not only shows the full range of search options possible, but also illuminates the inevitable tradeoffs and losses of access that occur when researchers limit themselves to any one conceptual framework. In two chapters devoted to computers he examines the use of electronic resources and reveals both their advantages in providing access to a widerange of sources and also their limitations: what people are not getting when they rely solely on computer searches; why many sources will probably never be in databases; and what the options are for searching beyond computers.