The Secret of the Ages - The Secret of the Ages, sold over 300,000 copies during his life. Collier wrote about the practical psychology of abundance, desire, faith, visualization, confident action, and becoming your best. Collier's Books have recently been brought back to prominence from being referenced in the popular metaphysical movie The Secret. Moreover, Robert Collier's books have been popular with self help and New thought. After overcoming an illness he became fascinated with the power of the mind and how to use it to create success in every area.