A group of experts, coordinated by Pere Lluís Font, presents in this book the catalan contribution catalana in the field of philosophy, as well as social sciences -ideas- along-the twentieth century -days-, indicating the main trends, turning points and the most prominent figures. The book also presents a critical assessment in the international context and perspective for the future. Ricard Pié participates in this compilation with an explanation about urban development in Catalonia during this period.