"Comment is free," wrote Guardian editor CP Scott in 1921, "but facts are sacred". Ninety years later, publishing those sacred facts has become a new type of journalism in itself: data journalism. And it's rapidly becoming part of the establishment. Facts Are Sacred show how the Guardian Datablog does it. It reveals how data has changed our world and what it tells us. It's a manifesto for a new way of seeing things. And it shows how not only is data journalism changing in itself, it's changing journalism too. And the world.