I love, love, LOVE this series. It has all the elements of a great (in my opinion) teen novel. Or any novel, really.
1) It’s British. Need I say more?
2) It has ghosts.
3) It takes place in modern day, but has a throwback feel to another time – Victorianish – which is probably due to the fact that ghosts are real and becoming more and more prevalent (they also kill people) so progress has somewhat shifted to deal with the “Problem” as it is referred to.
4) The characters are completely believeable and likeable.
5) The teens in this world are powerful because only they can see the ghosts and destroy them, but the struggle with adult authority is still a major underlining theme throughout the series.
6) It has a HINT of romance – the kind that is only present in a sentence or two in each book, but then it’s gone and you wonder if it was ever there at all. It grows slightly as the series goes on, but it’s not at all the main theme.
If you haven’t read the series, you really need to. And start at the beginning!