I lost a friend and colleague last week. Like all the best friends, he was an inspiration, an irritation – the grit in the oyster of thought – and an endless source of provocation, ideas and damn good lunches. He had a unique ability to make the inexplicable obvious. And vice versa. Most of us, if we’re lucky, manage perhaps a little of each of these during our lives, with family, friends and colleagues. Douglas managed to do it over more than twenty years and for millions of people around the world. The many thousands of messages on his web site all express a shared feeling of shock and incomprehension.