In 1944 the Library returns to the Ciutadella as the Library of the Art Museums of Barcelona. It is now a specialised municipal library. From this period we should point out the important work of the then, and up to 1985, director of Art Museums, Joan Ainaud de Lasarte. In those years Joan Ainaud gave a great boost to acquisitions, which went from 8,000 to 80,000 pieces.

1948-1985 In 1948 Joan Ainaud de Lasarte is appointed director of Art Museums

He is also appointed head of the Municipal Museums Operating Unit and secretary of the Museums Board. His many years in charge of the museums of Barcelona gave the definitive boost to the Library of the Art Museums of Barcelona, in particular the acquisitions policy, which in those years rose from 8,000 pieces to over 80,000.