Deeper and deeper, until it's dark.

I’ve just finished reading Terry Pratchett’s book ‘Night Watch’ (again!) and I must say it is one of his darkest novels yet. It seems that a lot of authors will go through a dark patch when they are writing a series. Just look at JKR, in the Harry Potter series. The series starts off with pretty easy going, as if she wants to gently nudge the reader into the world of magic and wizardry. But with every book the plot gets more sinister, darker and deeper. By the time she reaches Deathly Hallows there is almost nothing left of the humour that the book started out with. Then, suddenly at the end of the series, you get a few pages of light – Harry has grown up, the world is a good place and everything is going to be fine.
At least Pratchett went on to write a couple of funny books after Night Watch. Maybe it’s just built in to writers to do this kind of thing. Or maybe not, if we look at Stephen King, who could be pretty dark and deep throughout a whole series. But I suppose that the more a writer explores a subject, the deeper he or she is going to dig, finding all the dirty laundry and dragging it out to show to the readers. Almost like a rotten tooth being explored by the tongue, until at last the pain gets unbearable and the tooth gets taken off to the dentist where it is extracted and thrown in a dish, revealed for all the world to see, rotten and decayed.
At the moment I am looking for a good new series to start reading, and I’ll be looking forward to seeing how the writer delves deeper and deeper into the mysteries of his subject, and then to read some reviews on what other people thought of it.