John Stuart Mill in his "Autobiography" declares with truth that "the world would be astonished if it knew how great a proportion of its brightest ornaments, of those most distinguished even in popular estimation for wisdom and virtue are complete sceptics in religion." Many of these, as Mill points out, refrain from various motives from speaking out. The work I have undertaken will, I trust, do something to show how many of the world's worthiest men and women have been Freethinkers. My Dictionary does not pretend to be a complete list of those who have rendered services to Freethought. To form such a compilation would rather.