Sigmund Freud 
Interpreting Dreams 

By a detailed investigation of the universal phenomenon of dreaming, Freud discovered a radical new way of exploring the unconscious and recognized that dreams are a conflict and compromise between conscious and unconscious impulses. Through his insights about dreams, Freud was able to revise his methods of treatment for neurotic patients and develop, largely through this remarkable work, his revolutionary theories of the Oedipus Complex and of the profound importance of infantile life and sexuality for the development of adults.