The Amber Spyglass

I finished The Amber Spyglass by Philip Pullman the other day. What a fantastic book. The story line left me breathless at times. The characters of Lyra and Will develop to an incredible depth. The things they go through had me on the edge of my seat. Some of the other main characters, Mrs Coulter, Lord Asriel, Mary Malone, and so on really contribute to the story. I was pleased to see Iorek Byrnison back and making such a significant contribution.
Whenever I talked to people about these three books as I was still reading the third, I described the second book, The Subtle Knife, as filler (despite my review). Compared to Northern Lights, and The Amber Spyglass, it seemed to be lacking in depth. Having completed the trilogy, I realise that the Subtle Knife laid a lot of groundwork, introducing characters, the knife, and laying the foundations for events on The Amber Spyglass. So although, it is the weakest of the three books, it is essential to the whole story.
All three books: recommended!