PUBLIC LIBRARIES IN BARCELONA
Each Library has its timeschedule. They usally are open Monday to Saturday.
Nice libraries are Sagrada Familia or Jaume Fuster. See the whole network in http://sinera.diba.cat/search*
If you’re staying in Barcelona for a while, you may find the Network of Municipal Libraries useful. It is not only a wide network of small libraries distributed in all Barcelona but also a place to connect to the internet for free. The only condition is to have the library card that identifies you as a user of the Network of Municipal Libraries of the province of Barcelona. It allows you to use those public library services that require identification and to enjoy many advantages in the sphere of culture (discounts on entrance tickets, specialised shops, etc.). The card is free, does not expire and may be requested by any member of the public. This library card is valid in all public libraries in Catalonia. You will be requested to have an official ID to get the card (your passport would be enough). Here is the formular you have to fill in to get the card: http://sinera.diba.cat/screens*/formulari3.html. It can also be obtained directly in any library.
Unfortunately the choice of books in foreign languages tends to be limited.