The first part of this paper reviews different notions of personality boundaries in dynamic psychology. Although the explicit treatment of this topic was scarce, three different approaches may be discerned. Paul Federn's introduction of the concept, the notion of boundaries in object relation theories, and various contemporary notions subsumed under the heading “relational theories.” In the second part, the author reviews both experimental and clinical research and theory regarding the emergence of personality boundaries during the first eight weeks of development. Special attention is paid to the importance of developmentally most primitive mental representations of skin experiences for this process.