Cathy Pope has been Senior Research Fellow in the School of Nursing and Midwifery, University of Southampton since August 2003. Prior to this she worked as Lecturer in Medical Sociology in the University of Bristol medical school (1999-2003) and University of Leicester medical school (1994-1999). She co-edited, with Nicholas Mays, a popular introductory text, Qualitative Research in Health Care (2nd edition 1999, BMJ Books). Nicholas Mays has been Professor of Health Policy in the Health Services Research Unit at the London School of Hygiene and Tropical Medicine since May 2003. Before joining the School he worked in the Social Policy Branch of the NZ Treasury, at the King's Fund where he was director of health services research, at the Queen's University of Belfast, at the United Medical and Dental Schools of Guy's and St Thomas' Hospitals and in the NHS. Jennie Popay is Professor of Sociology and Public Health, Institute for Health Research, University of Lancaster. Her research interests include social and gender inequalities in health, the sociology of knowledge (with particular emphasis on lay knowledge about health and illness) and the evaluation of complex social interventions and she has published widely on these subjects. She is currently a commissioner and vice chair of Commission for Patient and Public Involvement in Health.