That ever so tedious misplaced apostrophe

Someone followed me on Twitter recently claiming to write 'Kid's books'.  Now I try so very hard to ignore misplaced apostrophes in the general public, but when a writer demonstrates a lack of understanding of the rules for them, I get a little bit upset.  Especially when they are writing kids' books.  It makes me wonder what standards they are setting for young readers.  So here's a quick lesson on the possessive apostrophe (which seems to be the one that causes most problems) purely for anyone who is confused about the rules.

I used to teach my students a little mantra and make them repeat it by rote every time they wrote an essay (love homophones too!)  for two weeks until they'd fixed it in their minds.  If people will only take the trouble to do this, they will never misuse the possessive apostrophe again.

It goes like this:

The girl's bag

The girls bag.  To find out where the apostrophe goes, you need to ask who does the possessing or owning.  In this case, it is the girl, therefore place the apostrophe after girl = the girl's bag.

The girls bags.  Well, of course it's possible the girl has several bags, but hopefully the context will make that clear.  If we assume there are several girls owning the bags, we ask the same question: Who owns the bags? 

In this case the answer is the girls, therefore, place the apostrophe after girls
= the girls' bags.

Let's try another:

The teachers' meeting

The teachers meeting is in the library. 

Question: Who 'owns' the meeting? Answer: the teachers (very unlikely to be one teacher having a meeting alone) so, place the apostrophe after teachers 

= the teachers' meeting is in the library.

The children's toys

It works exactly the same with plural nouns.

The childrens toys. Question: Who owns the toys?

Answer: the children.  This is already plural but the principle is exactly the same, therefore, place the apostrophe after children
= the children's toys. 

Consider:

The lady's (or ladies') shoes

The ladys shoes = the lady's shoes (one lady owning more than one shoe)

The ladies shoes = the ladies' shoes (several ladies owning more than one shoe).

So just ask yourself when you write kids books - who are the books for? Answer: the kids - therefore place the apostrophe after kids = kids' books.

Kids' books

It really is that easy.