Conquests by arms are trivial in their permanent effects compared with the conquests of mind over matter, In the world of thought, there are the sources of progress to be found, and it was a significant fact, and momentous in its significance, that men of learning in 1914 found it in their hearts to do homage for the first time to Roger Bacon. For long he suffered calumny and neglect; though unlike so many innovators in scientific speculation, it is true that he escaped torture and death at the hands of his contemporaries. He nevertheless suffered much persecution, as well shall learn in what follows. Contents: molding of Roger Bacon's mind; fruits of Roger Bacon's learning; astrology; alchemy; medicine; magic and the discovery of gunpowder.