In the analysis of Felix, Klein explored pathological inhibitions that hampered the thought processes of this adolescent. She discovered that thinking is born from sufficiently creative bonds between the internal parents. The concepts of internal object and unconscious fantasy constitute, in this sense, one of the most innovative aspects of this analysis. Klein argues that revisiting the early Œdipus complex in puberty is an indispensable preliminary to the joint development of psychical bisexuality and “ psychical puberty ”.