Madam Schoen-René's Bel Canto Book

America's Musical Inheritance: memories and reminiscences (1941) 

I have it, of course, having found my copy via Abebooks a number of years ago. The interesting thing is that mine is a presentation copy, being dedicated by Madam Schoen-René to a student with the name of Hall Clovis.

Hall Clovis (b. 1990) was a tenor who toured with his wife Eleanor Steele, singing duets, many of them commissioned by well-known composers/arrangers of the period, including Mario Castelnuovo-Tedesco, Darius Milhaud, and H.T Burleigh. The Steele-Hall duo were popular in the 1930's, and toured in Germany and America until the War changed everything.

Steele and Hall eventually divorced, and Hall settled down to life in Santa Barbara with Charles Lee, with whom he lived the rest of his life in the Summerland home of Leopold Stokowski. Steele, having been born into a family of some wealth (Steele underwrote Risë Stevens studies with Schoen-René), remarried a cattle baron, and become something of a philanthropist, leaving behind a foundation that is still in existence. Meanwhile, the University of Santa Barbara currently houses Hall's collection of manuscripts and recordings, which I have heard, the latter conveying a very refined musical world. All this to say: You never know what you may learn from a book after it arrives in the post.