Sigmund Freud developed psychoanalytic theory to explain the structure and functioning of human personality. Two of his most influential contributions are the topographical model and the structural model of personality. These models explain how conscious and unconscious mental processes influence thoughts, emotions, and behaviour. Freud also proposed that the ego employs various defense mechanisms to reduce anxiety and protect the individual from internal conflicts. The topographical model, introduced earlier in Freud's work, divides the human mind into three levels: the conscious, the preconscious, and the unconscious. The conscious mind consists of thoughts, feelings, and perceptions that are currently within an individual's awareness. It represents only a small portion of mental life and includes information that can be readily accessed at a given moment. Conscious processes are responsible for rational thinking, decision-making, and awareness of the external environment. The preconscious contains memories, knowledge, and experiences that are not presently in conscious awareness but can easily be recalled when needed. Information stored in the preconscious can move into consciousness through attention or retrieval. Examples include remembering a friend's name or recalling an address. The unconscious forms the largest and most influential part of the mind. According to Freud, it contains repressed wishes, unacceptable desires, painful memories, unresolved conflicts, instincts, and traumatic experiences. Although inaccessible to conscious awareness, unconscious processes strongly influence behaviour, dreams, slips of the tongue, symptoms of mental disorders, and emotional reactions. Psychoanalytic therapy aims to make unconscious conflicts conscious so that they can be understood and resolved. Freud later refined his theory by introducing the structural model of personality, which consists of the id, ego, and superego. These are psychological