2023 Reprint of the 1949 edition. Full facsimile of the original edition and not reproduced with Optical Recognition Software. In this volume Hall explains the mind or mental culture by putting forward a series of separate, yet correlated, facts bearing upon the subject. For him the mind is man's sharpest tool and, having a razor-like edge, is quite capable of wounding the one who handles it unskillfully. The mind lifts man out of the darkness of ignorance into the light of truth, breaks the shackles that fetter the soul of the slave, and lifts aspiring humanity to a condition proximate to Deity. This same mind has also created all the slaves in the world; for the crafty intellects of despots have filled the earth with suffering and despair. While man has used his mind to make his world more beautiful, he has also used it to break the spirit and destroy the soul of his fellow beings. The mind is his greatest and truest friend and also is also his worst and most destructive enemy. Its potential for either good or evil is inconceivable. Hall explains how in ancient times every effort was made to prevent knowledge from coming into the possession of those who were vicious, selfish, ignoble, and untrue. In the twentieth century, however, the floodgates of thought have been opened and a veritable torrent of knowledge has spread over the world. Hence, the petty tyrant is gaining the power to become a great tyrant; the mediocre thinker, the power to become a miraculous thinker. The advent of AI obviously has much bearing on this newly relevant work.