Questions about the accuracy of library records, the behavior or attitudes of patrons, or the conditions of the books in the collection can often be answered by a random sampling study. Use of this time and money saving technique requires no special mathematical ability or statistical background. The concept of accuracy is didcussed and a table is provided to simplify the determination of an appropriate sample size. A method of selecting a sample using random numbers is shown. Three examples illustrate the application of the technique to library problems.