19.2 What to index
19.2.1 General principles
The indexer’s job is to identify and analyse concepts treated in the text so as to produce a series of headings based on its terminology; to indicate relationships between concepts; to group together information that is scattered in the text; and to synthesize main headings and subheadings into entries. All items of significance (names, places, concepts) should be entered, with correct page numbers and spelling. The needs of the user of the index should always be kept in mind, particularly in terms of what and where things will be sought: for example, in all but the most technical books an entry for humankind or mankind will be more helpful than one for homo sapiens. Looking at indexes of related works in the field can provide useful guidance.
Usually a single index will suffice: multiple indexes can be unhelpful and should not be provided without being agreed with the editor beforehand.
Indexes comprise a list of single headings or multiword headings followed by one or more locators (a page or page range, section, numbered paragraph, or some other division) to indicate where the topic is discussed in the text, or by a cross-reference to another heading. Entries complicated enough to require further division may have subentries within the main entry. In all but the most complex indexes, subentries within subentries (sub-subentries) should be avoided.
In some works it is desirable to highlight those references that include the principal discussion of a heading, and this is usually indicated by the use of bold type:
Editors of multi-author works must ensure as far as possible that contributors’ terminology and sources have been standardized to a single form throughout a work: the index may otherwise require frequent cross-references to guide the reader between variants.
19.2.2 Main entries
Main entries are those most likely to be first sought by the reader, and should be in a form that anticipates where the reader will look for them. They should be concise and consist of nouns modified if necessary by adjectives, verbs, or other nouns; unless house style dictates otherwise, they should start with a capital letter only if the word is capitalized in the text. Normally choose the plural form unless the noun is uncountable, e.g. lightning. If use of the singular is unavoidable, both can be accommodated through parentheses: cake(s). If singular and plural forms have different meanings, both forms may be used in the index.
Ignore passing or minor references that give no information about the topic. Do not include entries from the preface, contents, introduction, and other preliminary matter unless they contain information not found elsewhere that is relevant to the subject of the work. There is no need to index bibliographies or reference lists. There is usually no need to augment a heading with supplementary information from the text, though in some cases a gloss or other clarification in parentheses may prove necessary, such as in vom (proper name prefix).
Use cross-references or subentries where a single reference spans ten or more pages, or where lengthy strings of locators threaten to clutter the layout. An array of unqualified or undifferentiated locators several lines deep is tiresome and unhelpful to users, who will have to spend too much time trying to locate the information they seek. Any string should ideally be reduced to six or fewer numbers. For example,
from development 83–5, 100–7
from erosion 125–9
from logging 114–16
in Asia 117–18
in England 121–2
It is advisable to avoid main headings that echo the title or subtitle of the book. If such entries are essential, they must be succinct. In biographies or collections of letters, keep subentries relating to the subject to a reasonable minimum, confining them to factors of relevance.
Subentries are used chiefly to analyse a complex subject heading made up of two or more discrete categories:
beginnings of 2, 98
DNA’s role in 5–7, 10, 12–13
and inorganic matter 7, 10, 28–9, 48
as process, not substance 10, 11
Run together a simple heading with no general page references and only one category:
Sub-subentries can most effectively be bypassed by denesting the subentry containing the sub-subentry into a separate main heading of its own, cross-referring to it as necessary. For example, in the following
enclosure 198, 200, 201
industries 201, 205
It may not always be possible, or practical, to use subentries and sub-subentries to avoid long strings of locators in an exhaustive index—such as one containing numerous references to authors of cited publications, a separate index of authors, or an index of musical works.
An index is not intended to be an outline of the entire text: there should not be a subheading for every locator, and a list of subheadings all with the same locator should be condensed.
Notes should be indexed only if they give information not found elsewhere in the text. When there is a reference to a topic and a footnote to that topic on the same page, it is usually sufficient to index the text reference only. See
Cross-references are used to deal with such things as synonyms, near-synonyms, pseudonyms, abbreviations, variant or historical spellings, and closely related topics; they fall into two classes. The first, introduced by see, directs attention from one possible entry to a synonymous or analogous one, under which the references will be found:
farming, see agriculture
Dodgson, C. L., see Carroll, Lewis
Severus, Sextus Julius, see Julius Severus
The second, introduced by see also, extends the search by directing attention to one or more closely related entries or subentries. Two or more cross-references are given in alphabetical order, separated by semicolons:
clothing 27, 44–6, 105–6; see also costume; millinery
housing 134–9, 152; see also shelter, varieties of
tread depth 109; see also routine maintenance; tyre
Except in the case of reference from a non-preferred to a preferred term, or cross-references between acronyms and their full forms (see later in this section), do not use a ‘see’ cross-reference to a heading that takes up the same space as that occupied by the cross-reference itself. In
writers 25, 36–8
writers 25, 36–8, 50; see also authors
There must be no ‘blind’ cross-references: in other words, ensure that every cross-reference is to an existing entry. Cross-references to general areas rather than specific headings are often in italic:
In addition to inversion of proper names (
trial by jury
If the second and later words in the heading are also words that may be looked for, then additional inverse headings (and cross-references) can be made:
expression, right of
Inverse headings need not be made automatically for every multiword heading, as applied consistently they can have a significant effect on the index length. The selection will depend on the context: for example, the heading education, secondary above is not needed if education is the subject of the whole text.
Terms such as names of organizations are often referred to in the text in an abbreviated form. The indexer must decide whether to make a heading under the shortened form or at the spelled-out version of the term. It is generally agreed that widely known terms such as UNICEF and NATO can be indexed in their shortened forms without cross references from the spelled-out forms. However, the indexer will need to decide how much cross-referencing is appropriate for the likely users of the index. It may be helpful to include the full form in parentheses after the shortened version:
Oxford University Press, see OUP
A double entry may also be used:
Oxford University Press (OUP)