This chapter introduces essential psychoanalytic concepts that provide the theoretical foundation for applying supportive interventions. It offers a concise overview of key ideas, including the unconscious, object relations, attachment theory, and the notion of the basic fault. The discussion extends to the role of the facilitating environment in fostering psychological growth and explores central psychoanalytic constructs such as the Oedipus complex, the depressive and paranoid-schizoid positions, and resistance. Finally, the chapter examines transference and countertransference, highlighting their significance in supportive therapeutic work.