The "Today" presenter puts forward the case for agnosticism, arguing that doubt is not an easy option, but the only possible one in the face of humanity's profound questions. The main inspiration for his book was the Radio 4 series "Humphrys In Search Of God" which provoked the biggest audience reaction to any programme he has ever done. He describes his own spiritual journey, and the profound but surprising effect this series had on him. Now in paperback, this is another one for "The God Delusion" and "God Is Not Great" debate. 'John Humphrys is like Marmite; he provokes strong views' Jack Straw.

Bestselling author, radio presenter and national treasure John Humphrys tackles the big question through his own personal journey and argues that doubt is the only credible belief.