Great minds of the 20th century. Back row: A.A. Brill, translator of Freud's works, Sandor Ferenczi, one of Freud's disciples, Ernest Jones, author of "The life and times of Sigmund Freud". Front row: Sigmund Freud, Stanley Hall, president of Clark University Massachuetts and Carl Jung, Freud's foremost disciple from 1907 until 1912 when their association ended after Jung put forward his own ideas on the subconscious.