A microscope is a device used to view objects too small for the unaided eye. Objects that are only seen through a microscope are microscopic, which means very small. Microscopes provide an enlarged image of a small object. It is impossible to say who invented the compound microscope. Dutch spectacle-makers Hans Janssen and his son Zacharias Janssen are often said to have invented the first compound microscope in 1590, but this was a declaration by Zacharias Janssen himself halfway through the 17th century. The date is certainly not likely, as it has been shown that Zacharias Janssen actually was born around 1590. Another favorite for the title of ‘inventor of the microscope’ was Galileo Galilei. He developed an occhiolino or compound microscope with a convex and a concave lens in 1609. Galilei’s microscope was celebrated in the ´Lynx academy´ founded by Federico Cesi in 1603. Francesco Stelluti’s drawing of three bees were part of pope Urban VIII´s seal, and count as the first microscopic figure published (see Stephen Jay Gould, The Lying stones of Marrakech, 2000). Christiaan Huygens, another Dutchman, developed a simple 2-lens ocular system in the late 1600s that was achromatically corrected and therefore a huge step forward in microscope development. The Huygens ocular is still being produced to this day, but suffers from a small field size, and the eye relief is uncomfortably close compared to modern widefield oculars.

Anton van Leeuwenhoek (1632-1723) is generally credited with bringing the microscope to the attention of biologists, even though simple magnifying lenses were already being produced in the 1500s, and the magnifying principle of water-filled glass bowls had been described by the Romans (Seneca). Van Leeuwenhoek’s home-made microscopes were actually very small simple instruments with a single very strong lens. They were awkward in use but enabled van Leeuwenhoek to see highly detailed images, mainly because a single lens does not suffer the lens faults that are doubled or even multiplied when using several lenses in combination as in a compound microscope. It actually took about 150 years of optical development before the compound microscope was able to provide the same quality image as van Leeuwenhoek’s simple microscopes. So although he was certainly a great microscopist, van Leeuwenhoek is, contrary to widespread claims, certainly not the inventor of the microscope.

Microscopes are widely used in the field of science. There are various types of microscopes. The most popular for the masses is the optical microscope. Optical microscopes are those microscopes that use lenses for magnification. There is the simple microscope, and there is the compound microscope. A dissecting microscope is a pair of relatively low powered scopes that retains the three dimensional view of the world afforded to humans with two eyes. Most of us never see close things in 3D. When we look closely we close one eye and receive a flat image. The principles of stereoscopy were discovered at about the same time as the invention of photography (1839). Early photographers combined these two discoveries and recorded their world in three dimensional photographs. People of that era enjoyed looking through a stereoviewer that delivered the right image to the right eye and the left image to the left. Most people never consider that seeing the world in 3D is the result of two different images from eyes set very slightly apart.