""A List of Supplementary Operas"" is a book written by W. L. Hubbard and published in 1910. The book is a comprehensive guide to operas that are not commonly performed but are still worth considering for production. It includes a list of operas from various composers and periods, along with their synopses, characters, and musical scores. The book also provides recommendations for staging and production, as well as advice for directors and performers...