This chapter briefly reviews some of Sigmund Freud's major theoretical writings. Freud had already mentioned the significance of dreams by 1893. While writing Studies on Hysteria, Freud conceived of the dream as symbolically representing certain aspects of every normal person's waking life. Freud's assumption that dreams occurred every night implies that in all humans there is enough capital in the unconscious to energize a nightly dream effort regardless of the person's psychological well-being. In the Dream Book, in addition to theorizing about the role of the unconscious, primary and secondary processes, the role of censorship in dreams, regression, and other important topics in psychoanalysis, Freud also put forth the beginnings of what has been called the topographic model. Freud tells that one can proceed chronologically and get the dreamer to bring up his associations to the elements of the dream in the order in which those elements occurred in his account of the dream.