Edwin Land introduced the world to instant photography with the Polaroid Model 95. This camera, and subsequent models, used a peel-apart system that combined the negative with developing chemicals and photographic paper to deliver an instant print.
While this was amazing in its own right, Polaroid took the world by storm with the release of the SX-70 in 1972. Gone were the sticky, messy, peel-apart photos, replaced with an elegant framed image that developed in front of your eyes.
This system delivers our modern conception of instant photography, and provides the basis for systems like Fujifilm's Instax as well as modern Polaroid films. Sometimes, waiting for your film to be processed just takes too long!