8. Indexing

Style and Format

Figure 8-1 shows two examples of the indented indexing style (as opposed to the run-in style). One example shows the index format for unnumbered chapters, the other example is for numbered chapters. The only differences between the two examples are the format of the page numbers and the use of "to" as a separator for page ranges in the book with numbered chapters.

    Figure 8-1 Index Formats

Nested Entries

Many technical documents use up to three levels of nested entries: primary entry, secondary entry, and tertiary entry. Each entry level is indented from the previous level. These three levels appear as follows:

    primary entry
      secondary entry
        tertiary entry

The primary entry is the principal subdivision of an index. A simple primary entry comprises the entry and a page number. A primary entry comprising several page numbers is usually divided into secondary entries. Each secondary entry must bear a logical relationship to the primary entry. A secondary entry comprising several page numbers may be further divided into tertiary entries. Each tertiary entry must bear a logical relationship to the secondary entry.

In indented style, each secondary entry and each tertiary entry begins a new indented line (unless there is only one secondary entry). If an entry runs over the width of the column, it is indented. This is known as a flush-and-hang style. For entries longer than the column width, the first line is set flush and the rest of the entry is indented below it.

    Least-Recently-Used (LRU) Ring functional
      description, 3-17
      elements of, 3-24

Page Number Style

A common indexing style calls for a comma and a space to be inserted between the entry and the first page number. Subsequent page numbers are separated with a comma and a space. Page numbers appear in ascending order.

Often, the primary entry that has two or more secondary entries does not have any page reference itself.

    functional description
      input block, 2-3
      introduction, 2-1
      output block, 2-33

Major Page References

In certain cases, you may want to identify a particular page as the main source of information for a given topic, especially if the topic cites two or more pages. You can identify the main page by marking the page number in bold.

    dragging operations, 13, 37, 114

Page Ranges

In an inclusive page reference spanning several pages, there are two common styles: first and last page numbers separated with an en dash ( - ); or a space, the word "to," and another space if you include the chapter number as part of the page number.

    screen adjustments, 6 - 12
    screen adjustments, 1-6 to 1-12

"See" and "See Also" References

Here are basic formatting rules for "See" and "See also" references. (There are also other acceptable styles.)

Italicize the words "See" and "See also."

    base window, 45

      See also pane

Place the "See" reference on the same line as the index entry.

    search, See find

"See" and "See also" references should never include page numbers. Use these references to direct a reader to another entry.

    floppy, See diskette

"See also" references should appear at the beginning of the entry. Place the "See also" reference on a line by itself, and indent the reference from the line above.

    aggregation scheme

      See also summarization, data

For more information, read the section "Creating "See" and "See Also" References."


Do not capitalize any word in an index entry, unless the word is a proper noun, an acronym, or an abbreviation that is supposed to be capitalized. Use standard rules for capitalization.

    subwindow command, 37
    View accelerator, 34


If an entry is followed immediately by page references, insert a comma between the entry and the first page reference, and between subsequent page references.

    scrolling, 12, 16, 27

Punctuate an inverted phrase to show the inversion.

    function keys, right-handed, 21
    text facility, editing functions, 7

No punctuation is used between a primary entry without page numbers and subsequent secondary entries.


      adjusting, 64
      extending, 59

Use a semicolon to separate multiple "See also" and "See" references.

    local-area network

      See also Ethernet; standards, networking

Special Typography

The index is subject to many of the same typographic style conventions found in the text of the document itself. For example, if file names and commands appear in Courier typeface in your book, then they should appear that way in the index.

    dump command, 28
    core file, 16
    rlogin problem, 166

Other types of special typography you might use in an index include bold for main page references and italics for "See" and "See also" references.