Boundaries are considered fundamental to the work of psychotherapy. Current literature shows that good boundaries provide a safe space for both the client and the therapist. There is significant writing on the risk and consequence of boundary violations. And yet, current research sheds very little light on the essence of boundaries. Using an Interpretative Phenomenological Analysis, this qualitative study offers insights into the experience of three psychotherapists, as they developed boundaries in their work as therapists. Three themes emerged: “boundary: a blanket term”, “what lies beneath: hidden behind boundaries” and “contamination”. It is found that that the word “boundary” is used broadly, to describe many different phenomena. Consequently, the word “boundary” is used to hide feelings which are uncomfortable for the therapist. The final theme is the concept of the psychotherapists’ personal-lives being contaminated by their work as therapists.