Sigmund Freud 
The Interpretation of Dreams 

In attempting a discussion of the Interpretation of Dreams, I do not believe that I have overstepped the bounds of neuropathological interest. For, on psychological investigation, the dream proves to be the first link in a chain of abnormal psychic structures whose other links, the hysterical phobia, the obsession, and the delusion must, for practical reasons, claim the interest of the physician. The dream (as will appear) can lay no claim to a corresponding practical significance; its theoretical value as a paradigm is, however, all the greater, and one who cannot explain the origin of the dream pictures will strive in vain to understand the phobias, obsessive and delusional ideas, and likewise their therapeutic importance.