A good index enables the user to navigate sensibly through the work’s main topics and facts. How long it needs to be to accomplish this depends on the size and complexity of the work and the requirements and expectations of the readership. In general, a short index for a general book can account for as little as 1 per cent of the text it catalogues, while an exhaustive index for a specialist book can take up as much as 15 per cent. The editor should be consulted before preparing the index to a printed book, as length constraints may apply, such as those needed to make an even working (
The index is a vital component of the work, directly affecting the text’s usefulness for the reader. This chapter provides some general guidance on producing and checking an index for those not trained in indexing. However, if you are an author who needs an index, especially for a large or important work, it is strongly recommended that you consider using a professional indexer. Not only are they skilled at choosing, compiling, and ordering an index’s content using specialized software but they also bring a fresh pair of eyes to the text, which is invaluable in assessing the content from the reader’s viewpoint. Indexing software also reduces the problems associated with changes in pagination and ensures typographical consistency. Indexes are best submitted electronically, as rekeying errors are hard to spot.
19.1.1 Indexing in the digital age
Although at first glance free-text searching in digital products might seem to make indexes redundant, the chief disadvantages are that users must know precisely what they are looking for, and how to spell it; that multiple hits may be generated with no indication of which are of greatest relevance; and that underlying concepts which do not have obvious key terms are not retrieved. A well-formed index is therefore just as important in digital as in print publications.
Indexes are often created from first or second proofs, i.e. late in the production process, using page numbers as locators. With the exception of ebooks where fixed layout is desirable (such as highly illustrated titles), the possibilities offered by reflowing the same text into a great variety of digital formats means that the page is irrelevant as a concept other than for the print edition. This brings a major advantage to the indexing process as it can now start at a much earlier stage, as soon as a stabilized text becomes available. Two methods of indexing unpaged content are described here: embedded indexing and indexing to location markers.
Embedded indexing (EI) involves inserting actual index terms as hidden text marked with a functional identifier at appropriate locations in the electronic version of the indexed document. After pagination, EI software builds the index automatically by associating the final page locations with each embedded index entry and performing the sorting, suppression of duplication, and formatting necessary to produce a usable index. Most of the common word-processing packages, including LaTex, include an EI system. The default is usually to produce an index with page locations, but an embedded index can be presented with hyperlinks for use in digital product. Because of its availability in word-processing software, embedded indexing is preferred by some publishers and by many authors producing their own indexes. It may be more time consuming for a professional indexer than production of a conventional index using specialized software. Authors making their own embedded indexes should also be aware that, unlike specialized indexing software, the default alphabetization routines of the word-processing packages may not fully implement the principles outlined below under
Tagging with code markers
An alternative approach is to mark the point in the text to which an index term is to be linked using a location marker rather than a page number. The location marker (known also as an ID, unique number, or tag) must be unique to each point to be marked. Apart from the use of location codes rather than page numbers, the construction of the index follows exactly the same course as a traditional index. It differs from embedded indexing in that only the location codes, not index terms, are inserted in the electronic text and the indexer compiles a separate, stand-alone index file.