This article relies largely or entirely on a single source. (August 2008)
A native of Milan, Sonzogno was the son of a businessman who owned a printing plant and bookstore. When he inherited the business upon his father's death he set about turning it into a publishing house, Casa Sonzogno, which opened in 1874. The company specialized in producing cheap editions of early Italian music, and became celebrated for its one-act opera contest, which began in 1883. Among the participants was Giacomo Puccini with Le Villi (1883) - who, in fact, did not win so that the opera was taken over by Giulio Ricordi, the competitor of Sonzogno. Pietro Mascagni's Cavalleria rusticana, submitted in 1889 and premiering in 1890, was by far the most famous opera to win the prize.
In 1894 he established a theater, the Lirico Internazionale, in Milan. He was also one of the first publishers in Italy to launch pocket-book editions of a huge range of classical authors from all over the world, a collection he called Biblioteca Universale. The price of these minibooks (11.5 x 17.5cm) was so low, from 1 to 3.5 lire, that anybody could easily afford a personal library of classics, fiction and non-fiction.
Sonzogno died in Milan in 1920.