The Hidden Staircase/The Mystery of the Ivory Charm (Nancy Drew, Book 2 & 13)
By Carolyn Keene.
Description
Nancy Drew is the daughter of the famous lawyer Carson Drew, and like her father, she's got an eye for a mystery. But this can often lead to danger. This is a two-in-one edition containing "Hidden Staircase" and "Mystery of the Ivory Charm". - from Amzon
ISBN(s)
0006945252, 9780006945253