 access librari colleg thi studi assum addit studi held promis analyt consider concept the basic approach survei compar tradit current profession idea direct access princip data-gather instrument documentari analysi opinion questionnair find documentari analysi includ research 1890 1970 direct shelf approach brows left problem unresolv evid resist establish method user the exhaust studi concept confirm open shelf librari--organ shelf classif rel locat--were meant arous intellectu social polit interest averag citizen affect democrat self-realiz definit brows vari greatli self-indulg untutor objection work benefici self-educ gener reader valuabl guidanc scholar 