Jürgen Habermas is a German philosopher and sociologist known for his work in the fields of social theory and political philosophy. He is best known for his concept of the public sphere, which refers to a space where individuals can come together to discuss and influence political action. His ideas emphasize the importance of communication and rational discourse in democratic societies. Habermas is also associated with the Frankfurt School, a group of scholars who explored the relationship between society, culture, and politics. His theories advocate for the role of dialogue in achieving mutual understanding and social cohesion, making significant contributions to contemporary debates on democracy and ethics.