Chris Evans, Honorary Professor, Universities of UDLA, Ecuador, trained in medicine and psychiatry, specialising in psychotherapy with trainings in individual analytic therapy, group analysis and family/systemic therapy. He always combined research with clinical work and his driving interest has been "how is it that we think we know what it is that we think we know?" ... which he admits may have been a bit generic for a really focused research career! However, it drove wide exploration of research and assessment methods, led him to co-create the CORE system (www.coresystemtrust.org.uk) and to co-lead over 30 translations of CORE instruments. He co-authored the first paper naming, as a vital complement to "evidence-based practice", "practice based evidence": the theme of this book. He is now a full-time freelance researcher holding personal chairs in Sheffield, UK and at UDLA, Quito, Ecuador.