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.

1955 Book-plate of the Library, done by Enric Cristòfol Ricart

This year the book-plate section is organized. Barcelona City Council holds a book-plate competition for the Library, with 2,500-peseta prizes to the two best ones, one for the etching technique and the other for drypoint. One of the winners is Enric Cristòfol Ricart and his work is reproduced for the use of the Library.

Among other artists taking part in this competition were Francesc d'Assís Galí and Joan Colom.