This book presents contemporary studies in qualitative psychotherapeutic research, examining their effectiveness in developing psychotherapeutic innovation and imagination. There is a focus on phenomenology, particularly given the growing prominence of interpretative phenomenological analysis (IPA). The book explores the tension between different forms of therapeutic knowledge—theoretical explicit knowledge, practice-derived explicit knowledge, and the crucial yet elusive tacit knowledge that emerges through clinical experience. While qualitative research methods attempt to transcend the limitations of quantitative approaches and access the communities of practice where tacit knowledge resides, the book questions their effectiveness in this pursuit. It argues that although phenomenological approaches offer valuable insights into both explicit and tacit dimensions of therapeutic practice, their increasing psychological orientation—rather than adherence to philosophical foundations—may ultimately constrain psychotherapeutic innovation and imagination. This volume will appeal to psychotherapists, clinical psychologists, qualitative researchers in mental health, and graduate students in psychology and counselling. It addresses key subject areas, including psychotherapy research methodology, qualitative approaches in mental health, IPA applications, philosophical underpinnings of therapeutic knowledge, and the ongoing debate around evidence-based practice in psychology. Academics researching psychotherapy and practitioners seeking to understand knowledge development and innovation in therapy will find this work particularly valuable. The chapters in this book were originally published as a special issue of European Journal of Psychotherapy and Counselling and are accompanied by an updated Introduction and a new Endnote.