In the final paper on the Oedipus complex, Klein develops her theories of the earliest infant stages of development, extending Freud's analysis of the Oedipus complex and laying a basis for her own subsequent conceptualising of the paranoid-schizoid position in the first six months of life.

In the final paper on the Oedipus complex, Klein develops her theories of the earliest infant stages of development, extending Freud's analysis of the Oedipus complex and laying a basis for her own subsequent conceptualising of the paranoid-schizoid position in the first six months of life.