The relationship between a director and his actors is one of the most important in film. A director needs to trust an actor to perform the things he asks, but the actor also looks upon the director for safety and guidance, especially if the subject material of the movie is controversial or difficult. Filmmaking is about rhythm, chemistry and collaboration, and for a film to succeed it needs the entirety of the cast and crew on the same page, which is why the great directors often use actors, cinematographers and editors they have good understandings with. Directors such as Martin Scorsese, Ingmar Bergman, Paul Thomas Anderson and David Lynch would often use a similar cast of actors in all of their films. And the benefits of doing that can be seen in all of their films, as all four men are amongst the greatest directors to ever live. Familiarity is also good for actors, as they are aware of the situation they'll be getting themselves in, and in a position of comfort, they will be more willing to go that extra yard needed. This list is calculated and devised on the greatness of the films the pairs made together, how they worked without each other, the amount of times they worked together, their impact on cinema overall and their legacy as collaborators.