That not really what it’s about. The books don’t really teach french at all. They explain – for example – what subject / object pronouns are and how to use them. This is the sort of thing that people often struggle with when learning any language as they know their own grammar intuitively but often haven’t examined it.
Still if you have them available to you you’ll know what they’re about and if it works for you or not. I found it helpful.
(not sure what HP means)
I haven’t studied grammar directly for a while now – I just immerse myself in French TV, music and books. Occasionally looking something up if I can’t work it out.
🙂
/edit – you’re talking about Harry Potter aren’t you… Je vais chercher mon manteau.