Grammar Question: Author OR Authors OR Authors' OR Author's ???!?

Question

Hi, I have a grammar question. Which one is correct for a section header?

Author's Index

Authors' Index

Author Index

Authors Index

This is so hard! Help! Thanks!!!

Answer 1

If there is more than one Author you would use Authors' index showing the possessive form of the plural noun.  If it is just one author you would use Author's index showing the possessive form of the singular noun.

Answer 2

Author's Index if there is one author.

Authors' Index if there is more than one.

's is possessive for singular subjects while s' is possessive for many subjects.  

Answer 3

Depends.  Is there more than one author?  What exactly is the content of the section?  If it is a list of contributing or cited authors, just write: "Index of Authors".

Answer 4

More than one author ►Authors´Index

One single author ► Author´ s Index