I’m currently poking my way through Tree Rings and Telescopes, a biography of A.E. Douglas written in the 1980s by George Ernest Webb. Douglas was the astronomer who invented the science of dendrochronology around the turn of the 20th century. He was looking for a way to study sunspot cycles, figuring they would be reflected in growth rings in the trees. What he ended up inventing was a fundamental tool for archaeology and for climate research. It was a time when it was still possible for a scientist to be a great generalist – for an astronomer to have a profound influence on fields completely outside his own.