Sigmund Freud was an Austrian neurologist and the “Father of Psychoanalysis.” He is best known for his theories of the unconscious mind and the defense mechanism of repression, and for creating the clinical practice of psychoanalysis. He is renowned for his redefinition of sexual desire as the primary motivational energy of human life, as well as for his therapeutic techniques, including free association, transference, and dream interpretation. He is considered one of the most important thinkers of the first half of the 20th century. 
In a September 9, 2007 New York Times article, 'Defender of the Faith?", author Mark Edmundson writes, "To the end of his life, he maintained his stance as an uncompromising atheist, the stance he is best known for down to the present. In The Future of an Illusion, he described belief in God as a collective neurosis: he called it “longing for a father.” But in his last completed book, “Moses and Monotheism,” something new emerges. There Freud, without abandoning his atheism, begins to see the Jewish faith that he was born into as a source of cultural progress in the past and of personal inspiration in the present.