Pier Francesco Tosi was a castrato singer, composer, and writer on music. His Opinoni de' cantori antichi e moderni... was the first full-length treatise on singing and provides a unique glimpse into the technical and social aspects of Baroque... Wikipedia
Books
Observations on the florid song, or, Sentiments on the ancient and modern singers
Observations on the Florid Song: Or, Sentiments on the Ancient and Modern Singers. Written in Italian by Pier. Francesco Tosi, ... Translated Into English by Mr. Galliard. ... To which are Added, Explanatory Annotations, and Examples in Musick
Observations on the Florid Song (1723) - Expanded Edition: Bel Canto Masters Study Series
2012
Observation of the Florid Song
Observations on the Florid Song; Or, Sentiments on the Ancient and Modern Singers. Written in Italian by Pier. Francesco Tosi, To Which are Added, Explanatory Annotations, and Examples in Musick The Second Edition
Opinions of Singers, Ancient and Modern, or Observations on Figured Song