English grammar

[Boto]

Can someone settle an argument? The car belonging to James is it a) James' car
or b) James's car?
Many thanks.

[Bev2007]

James' car

[toltol]

Bev's right!

[Gef]

Both are acceptable.

[alijangra]

The first option is used if you are referring to a plural, for example if you were talking about making a meal for a group of girls you would say the girls' dinner. The second option is used when referring to a singular so I would say that b) is correct. Sorry probably not much help as it contradicts the other answers given, I will check with my brother who is an English teacher.

[cruella]

I think you are spot on alijangra.

[Boto]

All of you - thanks very much.

[Ethel]

I've always thought a road near me looks wrong:

St James's Road

[Solarjunkie]

Bot are acceptable - it used to be that you could only miss out the s on a possessive name ending with an s if it were a saint's name, eg St Nicholas' church. Nowadays, 's is used for everything apart from Jesus. (are such things done in Jesus' name?)
So, Charles's book - which is how you'd say it - is fine, as is charles' book, but it looks a bit pedantic and old fashioned now.
There's loads about it in Eats, Shoots and Leaves.