Paul Salopek is walking the global trail of the first humans who migrated out of Africa in the Stone Age. His continuous 21,000-mile foot journey, called the “Out of Eden Walk,” is recorded in dispatches.
Homo sapiens is the ultimate tool-making animal.
The planet has been reshaped by our technology: by the fiber optic cable, by nuclear fission, by the agricultural combine, by the hyperlink, by the plastic bottle, by the predator drone, by the smart phone.
Yet we forget: For about 96 percent of our species’ 200,000-year-long history, only one material provided most of our needs: malleable stone. We rose to primacy above ...