Along this Final Master Project we will outline a comparation between the caractheristics of qualitative inquiry with case study and the documentary cinema of today. This comparative essay is structured around the review of four films that will allow us to examine several issues repeated the four diferent chosen films. As the text goes on we will see the relationship between this four documentary films that are, apparently, very different one from each other. In each analysis, we are going to draw small conclusions and, at the end of some analisys, we will find some open questions too. Finally, the the reader may find a comparative table that will allow them to see how, the listed caractheristics along this project, are being repeated in each film and they can use it, also, to analyze the same kind of documentary films in future cases.