Though its origins were older, the microscope was a child of the Renaissance, the period of European history that followed the medieval era. The Renaissance, which lasted roughly from the fourteenth to the seventeenth centuries, is considered by most historians to be the beginning of modern times. It was an exciting period of discovery and inquiry. Adventurers like Columbus explored new lands. Artists such as Rembrandt and Shakespeare created timeless works of beauty. Scientists and inventors like Leonardo da Vinci made amazing discoveries and fashioned powerful tools. During the Renaissance, dozens of groundbreaking discoveries were made just in the realm of science. Among them were the compass, the printing press, gunpowder-and the microscope.

The microscope revolutionized several branches of science, including medicine. True, the instrument required centuries of development before it was genuinely useful to medicine; in time...