I was quite obsessed with Wintersonnenwende (engl. The Dark is Rising) by Susan Cooper and with the whole series she wrote about the Light and the Darkness. I must have read it dozens of time and even had favourite music I would read the books to and that became connected with the story in my mind (Generator by Bad Religion, how weird is that?). And I will always see the cover of the 1980's German Paperback edition in front of my eyes, mustard yellow and bleak, although I found one cover for a newer English edition online which I really liked.
The book is actually quite dark and when I read an extract while sitting with friends around a fire when we engaged in a spot of wild camping, one of them squealed and begged me to stop as the book was too atmospheric and scary for this particular occasion ...
On 22 December we will finally be half-way out of the dark.