The Subtle Knife is the second part of the trilogy that began with The Golden Compass.
Philip Pullman is the author of many books for young readers, including two volumes related to the His Dark Materials trilogy: Lyra's Oxford and Once Upon a Time in the North. I suppose these things are partly temperamental; I know that some excellent writers make a great thing of planning every book before they write it; but it doesn't work for me.
Will is only twelve years old, but he bears the responsibilities of an adult.
Following the disappearance of his explorer-father, John Parry, during an expedition in the North, Will became parent, provider and protector to his frail, confused mother.
In Lyra's world, everyone has a personal dæmon, a lifelong animal familiar.
This is a world in which science, theology and magic are closely intertwined.