Sergei Eisenstein (1898 – 1948)
Director of Strike (1925) and Battleship Potemkin (1925) and a pioneer of the use of montage, developing the “methods of montage”:
“The first and most basic is metric editing, based on the length of a shot. It creates the tempo of the film.
The second editing method is rhythmic montage, based on both the length of a shot and the dynamics of the scenes. In other words, it also considers the rhythm of the action depicted.
Next is the tonal editing method, which focuses on the lighting, shadows, and colors of the edited scenes.
The over-tonal method combines the first three method in a holistic approach.
The last and most complex editing method, and Eisenstein’s favorite, is the intellectual method. It creates new meaning through editing by combining shots on the basis of a conceptual connection between them.” 
Dziga Vertov (1896 – 1954)
Director of Man With A Movie Camera (1929). Coined the term ‘Kino Eye’, or film eye
Kino-eye = kino-seeing (I see through the camera) + kino-writing (I write on film with the camera) + kino-organization (I edit).” … “Kino-Eye means the conquest of space, the visual linkage of people throughout the entire world based on the continuous exchange of visible fact” … “Kino-Eye is the possibility of seeing life processes in any temporal order or at any speed” … “Kino-Eye uses every possible means in montage, comparing and linking all points of the universe in any temporal order, breaking, when necessary, all the laws and conventions of film construction. 
Man With a Movie Camera is full of various montage effects. Many of them were very fast paced, unusual for the period, and unmatched until the era of the music video.
Vertov uses montage to show a journey in a short period of time when he shows the process of production. 
Another use of montage in this film is cutting to shots that are visually similar, but, apart from that, have no connection. 
Vsevolod Pudovkin (1893 – 1953)
Director of Mother (1926). Believed “…Editing is not merely a method of the junction of seperate scenes or pieces, but is a method that controls the ‘psychological guidance’ of the spectator.” 
He developed 5 editing techniques that help to convey certain emotions:
- Leit Motif
- Contrast: Cutting between two drastically different shots forces the viewer to compare two opposing scenes in their mind. 
- Parallelism: Connecting scenes by matching certain elements within them. Often used to jump from one time period or location to another in a more elegant way. 
- Symbolism: Similar to parallelism, but provides visual metaphors for elements in the story. 
- Simultaneity: Also called cross-cutting. For example, cutting between two sides of a situation, making it seem as though they are taking place at the same location when they are, in fact, not. 
- Leit Motif: A recurring shot or scene that has some sort of meaning or symbolism.