His Dark Materials Series
What the series is about, according to Amazon: "These thrilling adventures tell the story of Lyra and Will — two ordinary children on a perilous journey through shimmering haunted otherworlds. They will meet witches and armored bears, fallen angels and soul-eating specters. And in the end, the fate of both the living — and the dead — will rely on them."
Number of books in the series: 3
Ages the series is best suited to: 8-12
Buy the books here: His Dark Materials Series ($21)