Here’s one I prepared earlier.

Apostrophes, how to use them, and why the New Zealand Herald is utterly wrong.

  Apostrophes have been around since the 16th Century. Their first job was to show where letters had been left out of a word, usually to make it fit on a line or sometimes just when printers had run out of a letter or two.

  A century or so later, they picked up their second use: to show ownership (possession). (Side note: it’s really the same use. So John his house was shortened to John’s house.)

Debate over how to use apostrophes properly was first recorded in the 17th Century. They’ve been a pain in the arse ever since. They don’t have to be though. Either by (1) learning their basic uses and applying common sense, or (2) bookmarking this post and following it blindly, you need never get it wrong again.

  Apostrophes only do three jobs.

1. Show ownership

The apostrophe goes after the person or thing doing the owning.

  The dog’s breakfast means the breakfast owned by the dog.
The woman’s hair. The porn star’s spa pool. People’s paper. John’s room.

The same goes when the person or thing is a plural, like “dogs” – The apostrophe goes after the person or thing doing the owning.

  The dogs’ breakfast means the breakfast owned by lots of dogs.
The girls' toilet means a toilet used by girls . Men’s room means a room used by men.

  What about when the person or thing doing the owning ends in S?

  The basic rule here – and this goes for a lot of questions of punctuation – is to spell it the way you would say it. (But see note 1)

  Bridget Jones’s Diary means the diary owned by Bridget Jones

  Prince Charles’s urologist means the urologist employed by Prince Charles

  Vaughn Davis’s house means the house belonging to Vaughn Davis. It gets an extra S because that’s how we say it.

  The Davises’ house means the house belonging to the Davises. It just gets an apostrophe (no extra S) – we don’t say “Davises’s house.”

  2. Show a contraction

A contraction is where two commonly paired words are joined to make one word.

  For example:

  I will becomes I’ll
They have becomes they’ve
We are becomes we’re

Apostrophes can also be used to show missing letters in combinations of words such as rock ‘n’ roll. Check the dictionary!

  3. Clarify meaning when writing about individual letters

  Say you wanted to ask how many times the letter A was in a sentence (well, you never know… ). “How many a’s are there?” uses an apostrophe to avoid the obvious confusion if you didn’t.

  Want to know more?

  Concise Oxford Dictionary (any recent edition). All punctuation marks are explained at the back of the dictionary.

  Eats, shoots and leaves: the zero-tolerance approach to punctuation (Lynne Truss). A readable and actually funny book about punctuation in general.

  Fowler’s Modern English Usage if you’re really, really interested in this stuff, you sick puppy.

  Note: Why we are right and The Herald is wrong

  When a word already ends in S, whether you show possession by adding “apostrophe-S” or just an apostrophe comes down to how you say the word. Some dictionaries and style guides don’t care either way; The New Zealand Herald has a blanket policy of always showing possessive forms of words ending in S by adding only an apostrophe. On this matter, The Herald is wrong and we are right. Written English is the printed equivalent of the way we speak. Speech came first and speech should guide our decisions wherever possible. The other problem with the Herald approach is that it leaves the reader with no idea how to say the word out loud – if a possessive form of a word was meant to end with two S sounds (Vaughn Davis’s house, Prince Charles’s elbow) there would be no way of knowing.#fail, as the young people say these days.