Ben Miller is an actor, comedian and author. You may know him best from the Johnny English movies or as part of the double act, Armstrong and Miller.    He has also written both science and children's books. His most recent book is called the 'The Boy who made the World Disappear', which he wrote for his son.   He talks to Krishnan about why his fascination with discovering the truth, why he went from the science world to the arts world and why he loves reading.