These are the principles whose guidance I follow in this book. No novelties will be found here. I shall draw, gratefully, from an older Christian wisdom. Sir Arthur Conan Doyle, the creator of Sherlock Holmes, also wrote an adventure story called The Lost World. In it, Professor Challenger and his friends climb to a supposedly inaccessible plateau in South America and there find both dinosaurs and a previously unknown pattern of human life. The story was clearly meant for boys from