3-D, also known as stereo photography, went through various technical phases over the years. The first method was to view a pair of framed metal plates with a special pair of glasses that were physically affixed to the frame. This was expensive and didn't go over very well.

The next big change came in the late 1800s with the development of a light-weight, hand-held viewer. It had a small hood and a pair of lenses on one end and a sliding bar on the opposite end that held the photograph upright. When the bar was set at the proper distance, the person viewing could see a 3-D image. This is commonly known as an Oliver Wendell Holmes viewer, because Holmes (Sr.) was credited as designing it.

The Holmes viewer was popular through the turn of the century, but gradually waned in popularity as it became thought of as old-fashioned and quaint. Stereo cards, often known as stereographs, were supplanted by picture postcards.

In the late 30s, however, two men decided to revive stereo photographs but they gave it a modern twist. First, they would use color transparencies (i.e. slides) instead of prints; they would use a very small format and mount several slide pairs together on a paper disc; and they created a fixed-focus, simple plastic viewer. The reel was dropped into place, a simple slide button rotated the disc and placed the next pair into position, and the person looking could view the transparencies by the light of day, or a lamp, or any other light source. They called it the "View-Master" system and they sold it through a picture postcard company out of Portland, Oregon called Sawyers sold millions of viewers and reels based on these simple concepts. At their height they even sold cameras (e.g. the View-Master Personal) to produce them. But the heart of the system was the simple viewer and the reel.

In 1966, GAF, who continued production but expanded the reel subject matter to include things like entertainment stills from movies and television shows, whereas GAF with moving the film stock from Kodachrome to Ektrachrome, with a resultant decrease in quality.

GAF had troubles of its own, and when it pulled out of the consumer camera markets, it sold off View-Master as well. They became part of the old toy company Ideal, which moved away from travel photos and more into television and cartoon tie-in images, and agressively marketed View-Master as a non-violent children's toy. Ideal was eventually purchased by über-toymakers Mattel and sold under the Fisher–Price brand.

View-Master continues in production, though marketed and supported entirely as a children's toy. Classic View-Master reels and equipment are still popular, though they've acquired the same old-fashioned and quaint image that killed the Holmes stereoscope era.