This set of four volumes is a rare find for any opera enthusiast. Written by Robert Lawrence, this hardcover edition of Wagner's Ring of Nibelung is a must-have for any collector. The books are in their original form, printed in 1939 by Grosset & Dunlap, and feature a dust jacket and illustrations by Metropolitan Opera Guild. The topics covered in these volumes are opera, and specifically, the Ring of Nibelung. The books are written in English and are perfect for those interested in the history of opera and the cultural significance of Wagner's works. This set is a great addition to any antiquarian or collectible book collection.