The Wizard of Oz / The Prince and The Pauper

From Author Wars - https://authorwars.com/publications/the-wizard-of-oz--the-prince-and-the-pauper-565125.html

Overview:

Title: The Wizard of Oz / The Prince and The Pauper
Author: L. Frank Baum, Samuel Clemens
Year: 1965
Publisher: Grosset & Dunlap
Pages: vi+186
Binding: Hardcover
Type: Omnibus
Title Reference: The Wizard of Oz
Notes:
Dos-a-dos with Samuel Clemens's The Prince and The Pauper (x+256 pp., 1965, illus. Frank Vaughn) No catalog number or price given, cover unsigned