What is an index?
"An index is a consciously designed method of finding mentions of subjects, persons, or ideas." (unknown)
An index is a map to the content of your book for the reader.
An index is an essential piece of any published book that does not want to be discarded after one use.
An index tells the reader this is a useful, important book that holds information that is easy to access.
An index is a piece of intelligent design, discerning and linking subjects, objects and people within the text.
An index is NOT a keyword list produced by a computer.