David M. Clark is the Professor of Experimental Psychology at the University of Oxford. He is well-known for his pioneering work on the understanding and psychological treatment of anxiety disorders: especially panic disorder, social anxiety disorder, health anxiety and PTSD. David and his team have successfully developed and evaluated online versions of their social anxiety and PTSD treatments. Recently, he has also focused on the general problem of how to disseminate effective psychological treatments within healthcare systems and is one of the architects of the English Improving Access to Psychological Therapies (IAPT) programme. Currently, the IAPT programme treats around 640,000 people with depression or anxiety disorders each year and reports clinical outcomes on almost everyone. 2 in every 3 treated people reliably improve and 50% recover. David is the UK Government’s Clinical and Informatics Advisor for the program. He has received numerous awards and prizes, including Lifetime Achievement awards from the British and American Psychological societies.