A microscope is an instrument used to view small objects that cannot be seen by the naked or unaided eye. The science of investigating small objects using such an instrument is called microscopy and the term microscopic means minute or very small. Microscopes give us a large image of a tiny object. The microscopes we use in school and at home trace their history back almost 400 years. The first useful microscope was developed in the Netherlands in the early 1600s. There is no exact date as when it was invented. There is also confusion about who invented the first microscope. History credits three different eyeglass makers for the invention: Hans Lippershey, Hans Janssen, and his son, Zacharias Janssen. The most common type of microscope, and the first to be invented, is the optical microscope. The optical microscope is an instrument containing one or more lenses that produce an enlarged image of an object placed in the focal plane of the lens. There are, however, many other microscope designs. It can largely be separated into two classes, the optical theory microscopes and scanning probe microscopes.

Optical theory microscopes are microscopes which uses the function of optical theory of lenses in to magnify the image generated by the passage of a wave through the sample. Electromagnetic waves are used in optical microscopes and electron beams are used in electron microscopes. For Optical Theory Microscopes, there are 3 types. These are the Compound Light, Stereo, and the electron microscope. The stereo or dissecting microscope uses two separate optical paths with two objectives and two eyepieces to provide slightly different viewing angles to the left and right eyes. In this way it produces a three-dimensional (3-D) visualization of the sample being examined. The stereo microscope is often used to study the surfaces of solid specimens or to carry out close work such as sorting, dissection, microsurgery, watch-making, small circuit board manufacture or inspection, and the like. Great working distance and depth of field here are important qualities for this type of microscope. Both qualities are inversely correlated with resolution: the higher the resolution, the smaller the depth of field and working distance. A stereo microscope has a useful magnification up to 100×. The resolution is maximally in the order of an average 10× objective in a compound microscope, and often much lower.

The stereo microscope should not be confused with a compound microscope equipped with binocular eyepieces. In such a microscope both eyes see the same image, but the binocular eyepieces provide greater viewing comfort. However, the image in such a microscope is no different from that obtained with a single monocular eyepiece. Recently various video dual CCD camera pickups have been fitted to stereo microscopes, allowing the images to be displayed on a high resolution LCD monitor. Software converts the two images to an integrated Anachrome 3D image, for viewing with plastic red/cyan glasses, or to the cross converged process for clear glasses and somewhat better color accuracy. The results are viewable by a group wearing the glasses.