Custodial divisions throughout the Library of Congress routinely create inventories, registers, indexes, and guides, which describe and facilitate access to the collections under their control. All of these descriptive access tools are commonly called finding aids. They are prepared to assist researchers in locating materials relevant to their research, and they usually contain far more detail about a collection than can be captured in a catalog record. They often provide information about a collection's provenance and the conditions under which it may be accessed or copied; biographical or organizational histories related to the collection; a note describing the scope and content of the collection; and progressively detailed descriptions of the parts or components of the collection together with the corresponding call numbers, container numbers, or other means for researchers to identify and request the physical entities of interest to them.