An Index Versus a Search Engine
The index is the key to the book. Good indexes provide an entry point -- allowing the reader quick access to ideas that shape the text. By acting as a road map to the important concepts and ideas in the work, the index enhances the voice of the author on behalf of the reader.
A non-fiction work is not necessarily well served by a search function, which merely returns all instances of a term or phrase. Search engines certainly have a place in information retrieval and coexist quite nicely in eBooks. But exclusively using search in a large online document, or in an eBook, may return many instances of words or phrases irrelevant to the search, and frequently, so many instances of a term as to render the search frustrating.
Search engines, since they depend on instances of specific combinations of individual words, are unable to discern complex concepts or ideas. Additionally, users of search engines may not have the skills to frame a search with enough specificity to return the desired content. A well made index is a knowledge map to the content, employing very selective terms (locators or pointers) devised by the indexer.
Indexers are experts in the taxonomies used in specialized subjects, allowing readers to access information when exact terms may not be at their disposal. For example, if your searching in a serious medical journal for "heart attack," a search button may never find "myocardial infarction," even though both terms essentially mean the same thing.
A good index however is targeted at a particular audience. In the above example, if lay readers were the primary audience, the indexer would include a "see" entry for heart attack pointing to myocardial infarction:
heart attack. see myocardial infarction
The index can also direct the reader to related and important relevant data with "see also" entries:
myocardial infarction. see also atherosclerosis, cholesterol
Further refinement of content organization is reflected in index subheadings, sometimes called sub entries. These are constructed in such a way to modify and expand on the main headings of an index. Usually subheadings are indented (see insert above left), but other formatting choices exist. By organizing data hierarchically, the indexer provides the reader with a concise view of relevant information, making it easy for the reader to locate concepts and ideas in the text.
A non-fiction work is not necessarily well served by a search function, which merely returns all instances of a term or phrase. Search engines certainly have a place in information retrieval and coexist quite nicely in eBooks. But exclusively using search in a large online document, or in an eBook, may return many instances of words or phrases irrelevant to the search, and frequently, so many instances of a term as to render the search frustrating.
Search engines, since they depend on instances of specific combinations of individual words, are unable to discern complex concepts or ideas. Additionally, users of search engines may not have the skills to frame a search with enough specificity to return the desired content. A well made index is a knowledge map to the content, employing very selective terms (locators or pointers) devised by the indexer.
Indexers are experts in the taxonomies used in specialized subjects, allowing readers to access information when exact terms may not be at their disposal. For example, if your searching in a serious medical journal for "heart attack," a search button may never find "myocardial infarction," even though both terms essentially mean the same thing.
A good index however is targeted at a particular audience. In the above example, if lay readers were the primary audience, the indexer would include a "see" entry for heart attack pointing to myocardial infarction:
heart attack. see myocardial infarction
The index can also direct the reader to related and important relevant data with "see also" entries:
myocardial infarction. see also atherosclerosis, cholesterol
Further refinement of content organization is reflected in index subheadings, sometimes called sub entries. These are constructed in such a way to modify and expand on the main headings of an index. Usually subheadings are indented (see insert above left), but other formatting choices exist. By organizing data hierarchically, the indexer provides the reader with a concise view of relevant information, making it easy for the reader to locate concepts and ideas in the text.
....indexing is a highly skilled science, and it would be as foolish for a writer unversed in its mysteries to compile his own index as it would be for him to attempt, without the requisite knowledge, to cut type from which his book is to be printed.
-- Bernard Levin (1989)
