The project documented in this report identified barriers researchers encounter in gaining access to--i.e., identifying, acquiring, handling, and using--published information and measured the seriousness of the more significant barriers. Fifty-one barriers were identified, and a method of measuring their seriousness was developed. Thirty of the more important barriers were selected, and their seriousness was measured on the basis of an interview questionnaire administered to 60 researchers in the human and natural sciences. The major findings were as follows: (1) researchers experience many different types of barriers; (2) the effect of barriers is usually detrimental; (3) the seriousness of barriers remains constant over time and does not decrease; (4) the library or information system is exposed to the barriers and incorporates them from outside its operational environment; (5) the library or information system, which essentially exists to promote access to published information, also causes barriers; and (6) the method for measuring the seriousness of the barriers seems sound. The primary recommendations include identifying barriers within library or information systems so they can be removed or reduced; having researchers, editors, and publishers assume more responsibility in ensuring fewer barriers to their published materials; and activating library and information systems in the information life cycle. Sixty-one tables and 9 figures supplement the text. (385-item bibliography) (SD)