The great Enrico Caruso taking us through the vowels as shown in Caruso's Method of Voice Production: the Scientific Culture of the Voice (1922) by Pasqual Mario Marafioti. When he died in 1921 Caruso left behind him approximately 290 commercially released recordings, and a significant mark upon on the opera world including more than 800 appearances at the New York Met. He is considered by many to be truly the world's first popstar.
