The subtle knife is a sequal to the northen lights ( which I would of done exand the second book in the his dark materials trilogy. it continues on from the last book, the northen lights. where Lyra and her deamon (spirit animal) Pantalimon travel into another world. I am loving this book and I highly reccommend it for anyone from ten to ten thousand. Enjoy
Warning: this book does contain drug use (alchohol) and religous refrences.