Explanation. The concepts of Part Two, as known today, are inconceivable without the fundamental discoveries of Freud about the nature of the unconscious and without his contributions to the essential problem of inside and outside. The more specific concept of internal world starts with Ferenczi (1909), continues with Abraham (1924), and has a new, explosive, and fundamental development in Melanie Klein. As is easily understandable, the concepts developed here are mainly in the atmosphere of Freud and Klein. Starting from them, our hope is to go further in the explanation of this puzzling and fascinating world.