David Campbell is a well-established clinical psychologist, who works as a trainer and clinician for the National Health Service at the Tavistock Clinic in London, and also as a freelance consultant to teams and small organizations. For many years he has been interested in developing techniques for working with organizations that incorporate the principles of systemic thinking. His work has led to consulting and training projects throughout the U.K. and Europe for both public and private sector institutions. He has written several articles and books on this subject and is a co-editor of the Systemic Thinking and Practice Series, containing thirty-nine books, which has promoted many new ideas in this field.