The Sword of the Spirits (boxed set)

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Overview:

Title: The Sword of the Spirits (boxed set)
Author: John Christopher
Year: 1980
ISBN-10: 0020427700
Publisher: Macmillan
Price: $7.95
Binding: Paperback
Type: Omnibus
Title Reference: The Prince in Waiting
Notes: This is not an omnibus, but a boxed set of three volumes of the series. It is not known whether this is a packaging of individual printing of each title with each book having its own price and ISBN.