Mark Williams is Emeritus Professor of Clinical Psychology at the University of Oxford. He is a Fellow of the British Psychological Society, the Academy of Medical Sciences and the British Academy. With his colleagues at Oxford and Cambridge, he co-developed Mindfulness-Based Cognitive Therapy (MBCT) which clinical trials have shown to be as effective as medication and therapy for depression. The National Institute for Health and Care Excellence (NICE), working on behalf the National Health Service, now recommends MBCT as a primary treatment for depression.

Dr Danny Penman is a mindfulness teacher and bestselling author. He is co-author, with Professor Mark Williams of Oxford University, of the acclaimed Mindfulness: A Practical Guide to Finding Peace in a Frantic World. This book is credited with popularising mindfulness and is now prescribed across the UK's National Health Service for such conditions as anxiety, stress, depression and chronic pain. In 2014, he won the British Medical Association's Best Book (Popular Medicine) Award for Mindfulness for Health: A Practical Guide to Relieving Pain, Reducing Stress and Restoring Wellbeing (co-written with Vidyamala Burch). His journalism has appeared in the Daily Mail, New Scientist, The Independent, the Guardian, and the Daily Telegraph.