David Winter is Professor Emeritus of Clinical Psychology at the University of Hertfordshire, UK. He spent most of his working life practicing as a clinical psychologist and personal construct psychotherapist in the English National Health Service. He has published over 150 books, papers, and chapters, and his current research interests include the application of personal construct psychology in understanding the experiences of perpetrators and victims of extreme violence.Peter Cummins is a clinical psychologist who qualified as a personal construct psychotherapist in 1988, at the Centre for Personal Construct Psychology, United Kingdom. He retired from the National Health Service in 2010 after 34 years of clinical practice. His main therapeutic foci have been on working with anger, and working with couples. Harry Procter is a clinical psychologist and Visiting Professor at the University of Hertfordshire, UK. He conducted his doctoral research in the early 1970s at the Department of Mental Health at the University of Bristol, UK, applying personal construct psychology to family processes and initiating the development of a systemic constructivist approach to family therapy. He has since published over 50 papers and chapters covering many topics, including family therapy for children and adults with mental health and learning disabilities.Nick Reed is Director of the Centre for Personal Construct Psychology at the University of Hertfordshire, and he led the organization of the 2015 International Congress on Personal Construct Psychology. He is a personal construct psychologist working in a range of contexts, including organizational development, education, and environmental sustainability.