In this chapter, I am thinking about the issues of memory and the writing of personal memoirs, and how this impinges on our professional work. My title is drawn in part from the work of theoretical physicists who can hypothesise about the existence of dark matter by measuring the deformations it causes in surrounding stars and galaxies. What I suggest here is that there may be limitations in keeping strictly to disciplinary boundaries, and our professional lives may defy our efforts to box them in. The opening of doors to a more extensive world of ideas is often helpful, both for psychoanalysis and for the fields that it can illuminate and by which it can also be illuminated. I use the example of the publication and critical reception of my own memoir, Pieces of Molly to make links with our professional selves and our clinical work. I draw on the work of Freud, and other seminal thinkers in the field, as well as my own clinical work to illustrate the ways in which mental space and the memories within it can be contained and transformed over time, but also can be beset by both internal and external saboteurs.