you ‘had better not’ read it...

Perhaps there is some logic to it, but I'd have to sit down and think about it some more. Language isn't always logical, in any case; nor should it be.

Maybe this lack of logic results from sb's mistake or not knowing proper grammar...

Ummm...maybe because one means "Don't go" and the other means "Go." Meaning - the two uses have nothing to do with each other.

Are you serious?
the reason the had and not are seperate is because they are meant to be.
Had better not - a threat saying that one should not do something if he does not want something to happen to him
Hadn't you - improper grammar "had not you" ????
I suppose it means you should

you should vs. you should not

two different meanings.
you tell me why the not is not next to the had.
:)

Ben, if your best answer to a grammar question is essentially, "because that's the way it IS, dammit, and if you disagree, then up yours," then maybe you should reconsider posting.

Well in the first 'not' negates the action as in 'not going' 'not walking' while in the second is the negative form of a past tense event. 'To have had' or 'To not have'

I think 'shouldn't you go now?' would be more logical.