In 1921, Montessori published the first edition of the Manuale di pedagogia scientifica with a preface by Antonio Labriola, a socialist politician and economist. The book was dedicated to Marquise Maria Maraini Guerrieri Gonzaga, a friend and supporter of Maria Montessori. The second edition of the book, expanded compared to the previous one, was released in 1930, and the third in 1935. These latter two editions featured a preface by Nazareno Padellaro, a prominent pedagogue of the regime in the 1930s.

The 1921 edition is the Italian version of the book Dr. Montessori's Own Handbook, published by William Heinemann in 1914, also dedicated to the Marquise and with a preface by Maria Montessori herself. In the 1910s, as the method was being disseminated and applied in the English-speaking world, there arose a need for a text that would be easily accessible to teachers. Within this text, they could find a detailed list and explanations of the activities conducted in the Children's House.

All Italian editions were published by Alberto Morano in Naples and included a photographic section that documented the proliferation of Children's Houses and primary schools in the capital city of Campania.

In 1918, the “Società Amici del metodo Montessori” (Society of Friends of the Montessori Method) was established in Naples, promoting training courses in collaboration with the city Council. In the early 1920s, Naples emerged as a highly active Montessori hub, thanks in part to the training and supervision efforts led by Giovanna Maria Fancello, a student of Montessori since the “Course of Scientific Pedagogy” held in 1909 in Città di Castello.

By 1923, Naples boasted a 'Montessori district,' comprising sixteen classes spread across five different locations, serving eight hundred children. Additionally, there were thirteen sections dedicated to Children's Houses and primary schools, attended by approximately six hundred children. All teachers held the Montessori title.