The library for La Mina is a public building which rises at the heart of one of the most historically conflictive neighborhoods in Barcelona, where most of the area's gipsy families were relocated to during Franco's time. In the last decade the neighborhood has been the object of a deep transformation aiming towards the end of its social and urban marginalization. The decision to build a great public library in the area comes into the social transformation politics, through public equipment open to the public and capable of triggering urban transformation processes. The building is planned as emblematic and representative, capable of creating a recognizable image in the neighborhood and becoming a meeting place and a new center for the area which has always lacked public spaces. The aim of becoming a receptive and welcoming building is translated to a clear and spacious entrance, with a grand projecting cantilever to attract the people in the neighborhood. The first project, interrupted, was designed in the 90's by Enric Miralles and Carme Pinós. The present proposal recovers a part of the previous intervention, the multi-purpose hall, including it in the new building which serves as a great container. The hall is lighted with zenithal natural light, allowing to open some of the peripheral walls and creating an easy access which turns it into a great entrance hall and an area for temporary exhibitions and momentary events. The entrance of light through the façades and the roof skylights creates an spacious indoor space with a high atmospheric quality. The second room, next to the hall, becomes the central area of the library. This room also enjoys the natural light through the roof, filtered by mezzanines and vegetation. Other minor spaces are destined to smaller entities, workshops, formation areas, job offices, etc.