You open a gardening book’s index, find “roses” and meet a long column of page numbers. Just below it, smaller indented entries mention pruning, containers and diseases. Those subentries are a second level of navigation: they divide the broad topic into the particular discussion you need.
Read down before turning the page
In this invented example, “roses—containers, 84–87” is a more promising starting point for a balcony grower than the first page number beside “roses.” The main entry gathers a subject; the subentry adds a more precise question. A well-matched subentry can save several visits to passages that merely mention the plant.
Do not assume that indentation always means the same thing in every book. Check the index’s introductory note if one is provided. It may explain bold page numbers, illustrations, tables or other conventions used by that publisher.
Notice ranges and cross-references
A page range suggests that the relevant discussion extends across those pages, although it does not guarantee every sentence will concern your question. Open the passage and look at its headings and surrounding explanation before extracting a fact.
A “see” reference usually directs you to the term under which the material is indexed. “See also” invites an additional related search. If your everyday word has no entry, think of a broader term, a technical equivalent or a named person associated with the subject.
For a research note, record the edition as well as the page number. Pagination can change between editions and formats. The index sends you into a particular book; it is not a universal location system for every version of the text.
Finally, distinguish the index from the contents page. Contents shows the book’s planned sequence of chapters and sections, while the index helps you approach it through selected subjects. Starting with a subentry does not prevent sustained reading. It simply gives that reading a more useful doorway when you arrive with a specific question.