Stop-motion Animation
Before the advent of computers for camera motion control and CGI, movies used a variety of approaches to achieve animated special effects. One approach was stop-motion animation which used realistic miniature models (more accurately called model animation), used for the first time in a feature film in The Lost World (1925), and most famously in King Kong (1933).
The work of pioneer model animator Willis O'Brien in King Kong inspired Harryhausen to work in this unique field, almost single-handedly keeping the technique alive for three decades. While O'Brien's career floundered for most of his life – most of his cherished projects were never realized – Harryhausen achieved considerable success.
Harryhausen draws a distinction between films that combine special effects animation with live action and films that are completely animated such as the films of Tim Burton, Nick Park, Henry Selick, Ivo Caprino, Ladislav Starevich and many others (including his own fairy tale shorts) which he sees as pure "puppet films", and which are more accurately (and traditionally) called "puppet animation".
In Harryhausen's films, model animated characters interact with, and are a part of, the live action world, with the idea that they will cease to call attention to themselves as "animation", which is different from the more obviously "cartoony" and stylized approach in movies like Chicken Run and The Nightmare Before Christmas, etc.
Harryhausen's last film was Clash of the Titans, produced in the early 1980s. In 2009, he released colorized DVD versions of three of his classic black and white Columbia films (20 Million Miles to Earth, Earth vs. the Flying Saucers, and It Came from Beneath the Sea) and a film from the producer of the original King Kong (She).
Read more about this topic: Ray Harryhausen