Josep Perarnau i Espelt (Avinyó, Bages, 1928) is a Catalan priest, theologian and historian. He studied Theology in the Pontifical University of Salamanca, University of Rome and Munich. He became a priest in Barcelona. When the Faculty of Theology of Catalonia was created, he was appointed director of the seminary of theology. From this position he has made his historical researches. He is member of the Institute of Catalan Studies, and in 1990 he was appointed numerary member.
He is deeply interested in the Middle Ages history, and he has studied mediaeval manuscripts, specially the ones of Catalan authors. From his position as director of the Arxiu de textos catalans antics (ATCA) (Archive of Ancient Catalan Texts) of the Institute of Catalan Studies he has made valuable researches of unpublished works of the Middle Ages of authors such as Ramon Llull or Arnau de Vilanova.
He has gathered all the forgeries that the XIVth century inquisitor Nicolau Eimeric used in order to decree the existence of more than a hundred heresies in Ramon Llull's texts.
In 1993 Josep Perarnau was awarded with the Serra d'Or Critics Prize about research, in 1996 with the Cultural Heritage National Prize and in 1998 with the Narcís Monturiol Medal. These two last awards were given by the Generalitat de Catalunya (Catalan regional government). On 28 April 2009 he received an honorary degree by the University of Barcelona.