The media is the main source of political information having an impact on citizens. The concept of media bias refers to the disagreement over its impact on citizens and the objectivity of Modern biased media: lack of transparency, independence and objectivity. Mass media is considered the Fourth Vision to deal with the manipulation of public opinion. DOI: 10.1007 978-3-030-78818-6 2. In the book: Advances in Bias and Fairness in Information Retrieval, Second International.