For thousands of years Satan has been experimenting upon the properties of the human mind, and he has learned to know it well. By his subtle workings in these last days he is linking the human mind with his own, imbuing it with his thoughts; and he is doing this work in so deceptive a manner that those who accept his guidance know not that they are being led by him at his will. The great deceiver hopes so to confuse the minds of men and women that none but his voice will be heard.—Letter 244, 1907. MM 111.2