The ISBN of The Castle in the Forest is 9780812978490.
The ISBN of Castle to Castle is 978-2-070-21310-8.
The ISBN of The Castle in the Attic is 0823405796.
The ISBN of The Autumn Castle is 0732273943.
The ISBN of Castle - novel - is 0439176832.
The ISBN of The Glass Castle is 0743247531.
The ISBN of Escape from Raven Castle is 0440924065.
The ISBN of Forest Born is 1582348898.
The ISBN of Forest - novel - is 0670899208.
The ISBN of Castle Death is 0-425-10014-6.
The ISBN of Castle Roogna is 0-345-35048-0.
The ISBN of The Castle - novel - is 3-596-12444-1.
The ISBN of Castle Storm is 0-552-54547-3.