[Unedited] Robert Macfarlane with Krista Tippett

Robert Macfarlane is an explorer and linguist of landscape. His newest book, “Underland: A Deep Time Journey,” is an odyssey that’s full of surprises — from caves and catacombs under land, under cities, and under forests to the meltwater of Greenland. “Since before we were Homo sapiens,” he writes, “humans have been seeking out spaces of darkness in which to find and make meaning.” Darkness in the natural world and in human life, he suggests, is a medium of vision and descent, a movement toward revelation.