Answer: Index.
Step-by-step explanation:
An index can be found in a book or set of books, whether they are nonfiction, a monograph, etc. It´s a detailed alphabetical list of names, places, and subjects along with a reference to the pages on which they are used.
It typically points to page numbers, but sometimes leads to footnote numbers, chapters, or sections as well. The index can be seen at the end of the book and makes a piece of writing more approachable for readers, as they can turn straight to the information they want.