Meeting with Barack and Michelle Obama on the occasion of being awarded the Presidential Medal of Freedom (can be seen as the blue riband) for being an “extraordinary agent of change’. The medal is the highest civilian honour awarded in the USA. Hawking’s citation mentions his role in popularizing science, through his bestselling book "A Brief History of Time" and also his children’s books co-authored with his daughter, Lucy Hawking. The citation concludes, ‘His persistence and dedication has unlocked new pathways of discovery and inspired everyday citizens.’