THE ADVENT OF the microscope in the operating room revolutionized neur
osurgery. We traced the origin and evolution of this important inventi
on from the first magnifying lens to its practical application in neur
osurgery. The concept of magnification evolved from unexplained observ
ations in ancient times to the invention of the microscope by the late
16th century. In the subsequent 3 centuries, scientists made technica
l advances that greatly improved the power and utility of the microsco
pe. By the early 20th century, otolaryngologists became the first surg
eons to use the microscope in clinical surgery. After World War II, op
hthalmologists and vascular and plastic surgeons began using the micro
scope in the operating room, making further technical improvements. It
was a relatively small group of pioneering neurosurgeons in the late
1950s and 1960s who transformed microneurosurgery from a revolutionary
and unorthodox ''experiment'' into the standard of care in much of mo
dern neurosurgery.