Why are some books non-circulating or in-library use?
All books in Widener determined to be reference books are categorized as non-circulating, and the only exception we make is for foreign-language dictionaries needed for PhD exams. These appear in the catalog as "in-library use." While this policy may seem arbitrary, i assure you that the decision to classify a book as reference/non-circulating, is taken seriously and is made jointly by catalogers and reference librarians. We do so when the items are deemed essential research sources.
For example, The types of international folktales : a classification and bibliography : based on the system of Antti Aarne and Stith Thompson / by Hans-Jörg Uther is an important supplement/revision to the classic Stith Thompson folklore index, the standard publication that classifies folklore by motif. It might not be used frequently, but it serves a unique purpose and thus must be available in a research library such as Widener for use both by patrons and librarians.
To mitigate the disappointment of not being able to take out an item, we do have scanning available at no cost. You can scan the portions of the item you need and save them to a USB drive or send them to email.
(Answer composed by Deborah Kelly-Milburn)