The studies in this collection comprise a series of explorations into the revolutionary character of the Almohad movement in medieval North Africa and Spain and how it was expressed, including through compelling visual and auditory means. Almohad silver coins were minted square instead of round, and they carried no date, as if to indicate that a new era had begun. The new age was symbolized in the texts appearing on the coins, reminding Muslims that 'God is our Lord, Muhammad is our Prophet, the Mahdi is our imam', and that a new caliphate had begun. Almoravid mosques were purified and attempts were made to correct their orientation (qibla). Also, both non-Almohad Muslims and non-Muslims were obliged to learn the Almohad profession of faith, in what was in fact a forced conversion to the Almohad understanding of true religion. New scholarly elites - entrusted with the propagation and maintenance of Almohad beliefs and practices - were created by the Almohad caliphs. Philosophy flourished with Ibn Tufayl and Ibn Rushd (Averroes) serving the new rulers. These articles by Professor Fierro are an attempt at explaining what put in motion such a revolution, how it developed and changed, and the influences it had both in the Islamic and non Islamic worlds. Eight of the studies have been translated into English, from Spanish and French, specially for publication here.