Richard Aldrich 
Guide to the Ring of the Nibelung [PDF ebook] 
The Trilogy of Richard Wagner Its Origin, Story, and Music

Whilst the greatest effort has been made to ensure the quality of this text, due to the historical nature of this content, in some rare cases there may be minor issues with legibility. To endeavor to say much that is new or original about The Ring of the Nibelung would be a rash undertaking at this day. This little book is not such an undertaking. Its presentation of the origin, source, and musical structure of Wagner’s great trilogy is founded largely upon the labors of others. The author acknowledges a deep indebtedness to Hans von Wolzogen’s thematic analysis, to Mr. Henderson’s and Mr. Finck’s biographies of the master, to Miss Weston’s discussion of the legends, to Mr. Krehbiel’s Studies, and to other works in less degree.