In 1632, Antony van Leeuwenhoek was born in the city of Delft, a bustling hub of foreign trade permeated by canals, trees, and cobbled paths.1 By day, he worked as a city official and ran a small haberdashery business. By night, he made lenses. It was a good time and place to do so: the Dutch had recently invented both the compound microscope and the telescope. Through small circles of glass, scientists were peering at objects too far or too small to see with the naked eye.
