His Dark Materials The Amber Spyglass Book 3 The Amber Spyglass is about Will further traveling through the worlds, now in the possession of the Subtle Knife. Lyra has been taken and is kept sedated by Mrs. Coulter and has to be rescued – or be taken by enemy forces who have also found out where she is being kept. Accompanying Will are some new companions. Many places known through myths and fairy tales are simply other worlds in the multiverse. However, about 300 years ago something went wrong with dust and caused problems throughout them all. Mary Mallone, the physicist Lyra encountered in the previous book, is also traveling through the worlds, guided by the I Ching, which is another version of what the alethiometer is, settling eventually in a very interesting one populated by elephantine creatures that use seed pod wheels for transportation. The end battle is against the Authority (God) itself, represented by Metatron as well as the entire army of Heaven.