Sergel Eisenstein
Eisenstein was a pioneer in the use of montage. He developed the 'Methods of montage'
1. Metric
2. Rhythmic
3. Tonal
4. Overtonal
5. Intellectual
In his early movies he avoided casting stars, instead using stock characters from the relevant classes to the characters in the film.
Lev Kuleshov
He is believed by many to be the first film theorist following his montage theory. Kuleshov loved the juxtaposition of images which has become known as the Kuleshov experiment. In this he would cut shots of actors with meaningful images in order to show how editing affects peoples interpretation of what they see.
Dziga Vertov
Vertov was a Soviet pioneer for documentary and cinema theories. His practices and theories have paved the way for Cinema verite documentary film making.