Bear Grylls selects which projects to take on, he explains, by going for the riskiest. That may explain why this former SAS serviceman and adventurer climbed Everest at 23, circumnavigated the British Isles on a jet ski, and made an unassisted crossing of the Atlantic in an open inflatable boat, before switching to front extreme endurance TV shows such as Born Survivor, Wild Weekend and The Island.

His newest venture, he insists, is part of the same pattern of pushing himself to the very limit, though at first glance it looks like a curious departure from the norm. The man who, in a celebrated episode of Born Survivor, once emptied out the guts of a dead camel in the Sahara and then sheltered inside its carcass, is publishing a book about God.

The Telegraph London