This research portfolio comprises a culmination of research work spanning four years of part-time training on the Practitioner Doctorate course in Psychotherapeutic and Counselling Psychology (PsychD) at the University of Surrey. It contains three research reports: a literature review, and two qualitative studies. The literature review explored the extant literature on the therapeutic relationship with clients who meet the diagnostic criteria for borderline personality disorder (BPD). The first empirical study used an interpretative phenomenological analysis to gain an understanding of the experience of the therapeutic relationship for clients who meet the criteria for BPD. In the second empirical study a Foucauldian discourse analysis was carried out to investigate how the therapeutic relationship was constructed in dialectical behaviour therapy and whether these discursive constructs disrupt the dominant pejorative discourses on BPD. Clinical implications for both empirical studies are discussed in light of their findings.