What is an A-Z index?

"Information that cannot be found might as well not exist"

Nancy Mulvany, "Indexing Books", 2005

An index is not just a list of words from the text! An effective index identifies and highlights ideas and themes, analysed by the indexer and translated into helpful index entries. A well-constructed index will also allow many different ways of accessing the same information and could typically include:

synonyms - will your reader be looking for "vitamin B2" or "riboflavin"?
terms and their acronyms - will they want to search for "Anti-Social Behaviour Order" or ASBO?
inverted phrases - will they be looking for "sales records" or "recording sales"?