In the years Don Bosco had spent running his oratory and giving spiritual and practical instruction to the boys he had housed there, he relied on a different approach on education and general instruction which he believed to be superior to traditional educational methods which he labelled as a Repressive System of Education. On March 12, 1877, Bosco gave an opening address on the subject-matter of the systems of education during the day for the opening of the St. Peter's Youth Center in the new quarters of the Patronage de Saint Pierre in Nice, in which he first mentions the term 'Preventive System'. Upon his return to Turin, don Bosco wrote down the address as a polished essay under the title The Preventive System in the Education of the Youth which was published in 1877, which he included in the initial draft of the Rule for the Salesian Order. It espoused the values of reason, Religion, and loving kindness with a goal of producing 'good Christians and honest citizens'. This was the only attempt Don Bosco had at a systematic exposition of his educational system. Though the idea itself was not innovative by any means, Bosco having drawn the inspiration for his system through the contemporary criticisms of the punitive and outdated educational systems prevalent in Europe during his time, he was one of the first to combat and put these criticisms into practice.
Though Don Bosco's written works were little known outside of his own Order and the subscribers of his Salesian Bulletin, which he founded on August 1877, he wrote frequently and voluminously. Though Don Bosco was described as more of a man of action than a scholar, he was an exceptional historian. He penned the 1881 "A Compendium of Italian History from the Fall of the Roman Empire" which was translated and continued to the present time by John Daniel Morell, and was noted by scholars for its cultural importance on the knowledge base of ancient to modern civilization. He was also a skilled biographer. His two most well-known biographies were on his mentor Joseph Cafasso and one of his student, Dominic Savio, which would later be instrumental in his canonization.