The "auteur theory" is a way of looking at films that focuses on the director as the "author" of the film. If we agree with this theory, then we most likely think that a film is a reflection of the director, and that certain directors will give a film a particular tone and feeling that we can associate with them.
I agree with this theory only in a few cases. I believe there are directors who have a consistent vision of what they want to express, and the aesthetics, as well as the story that they develop in each film is equally consistent. Some examples would be Quentin Tarantino, Alfred Hitchcock, Tim Burton, Wes Anderson and Sofia Coppola. However, in most cases, the identity of the author is not as clear, and the movie's 'feel' is instead achieved through the collective effort of a large and diverse team of people.