Cross-referencing conundrums in book indexing

Most book indexes need some see also cross-references to direct the reader to relevant material elsewhere in the index as clearly as possible. But in large complex indexes this is not always straightforward. For example, how do you direct the reader to a subheading in another entry? Are ‘serial’ and ‘generalized’ cross-references ever justifiable? Should you ever make a see also cross-reference to an adjacent entry? Using examples mainly drawn from the author’s experience of indexing large and complex architectural and archaeological texts, this article discusses various options but concludes that in many situations there is no one perfect solution.