Weeding is one of the best ways to make long-term improvements to library collections, but it is also a difficult and sometimes painful task. In the tradition of previous editions, this book guides librarians in the process of methodical and efficient weeding. The book shows how to identify core collections versus the weedable items. The approach is based on the new understanding of the relationship between in-library use and circulation use. After reviewing current weeding practices and standards, the book discusses a variety of effective weeding methods, including the book card method, the spine-marking method, the historical reconstruction method, and the computer-assisted weeding. A new section has been added which includes suitable guidelines for weeding reference (noncirculating) collections. In addition, step-by-step procedures for each method are outlined and practicable considerations are discussed, such as how long each takes and how deeply weeding needs to be done. This entire edition has been thoroughly updated and revised and the process of weeding has been simplified. (AEF)