His book is on Kindle now, did you know that? Yes-sir-ee. You can now download Ferdinand Sieber's (1822-1895) book of vocal exercises for baritone for your Kindle (he wrote many books of vocal exercises which you will find with google). While you may have used Sieber's books of exercises in the past, or saw them on a shelf in a music library, I am guessing you didn't know who he was.
I remember seeing the book below at Patelson's Music Store behind Carnegie Hall some years ago before it closed. But I didn't know who Sieber was until I starting doing research on Anna E. Schoen-Rene (1864-1942), the musical daughter of Manuel Garcia and Pauline Viardot-Garcia. Schoen-Rene had lessons with Sieber in Berlin as a young woman before studying with PaulineViardot-Garcia in Paris in the 1880's.
Sieber also wrote a book on singing titled Katechismus der Gesangskunst (1885). I found a copy of the English translation - The Art of Singing, and Voice Culture (1908) - at Abebooks. Reading it, one gleans that he was an Old School boy.
Though Sieber did not have the enduring fame that has been accorded to Francesco Lamperti and Manuel Garcia, he was considered one of the foremost exponents of the Old Italian School.
HERR FERDINAND SIEBER, the famous singing-teacher, died at his home in Berlin on February 18th, from inflammation of the lungs. At the time of his death he was the greatest living exponent of the old Italian method of voice-culture. He was called by Leo Kofler the "apostolic successor" to the old masters, for he could trace his pedagogical descent directly from the days of Porpora. A short time before his death, Herr Sieber published a new book of vocal exercises, planned to bridge over what seemed to be a break in his voicetraining series already issued. His exercises are not only admirable for the voice, but they are also exceedingly tuneful, many being melodious enough for songs. Werner's Magazine 1885
Ok. So perhaps the 'greatest living exponent of the old Italian method' was stretching things a bit. After all, Manuel Garcia and his sister weren't dead yet. And they could trace their pedagogical descent through their father, Manuel Garcia the Elder, who studied with Giovanni Anzani, a student of the great Nicola Porpora. What was Seiber's lineage? He studied voice with Gorgio Ronconi, the famous Verdi baritone. And Ronconi was a student of his father, who had studied with a Venetian vocal master in the late 18th century. No small potatoes that.