Linear strips of LED lights are mounted in each bookshelf, which obviously makes the job of finding books somewhat easier. In the evening shots, the LEDs come into their own: the books seem to positively glow - an effect only emphasized by the choice of dark wood (hopefully sustainably sourced) for the shelves.
Visually at least, the choice of materials is striking: pale floors and furniture contrast with the shelves, and opaque glass walkways put the upper-most shelves within reach.
A series of tightly-packed skylights ensure that, during the hours of daylight, the library is positively bathed in natural illumination, and other than the bookshelf LEDs, artificial lighting appears to have been kept to an absolute minimum.
Buildings with highly-specialized uses lend themselves to highly-specialized and bold designs. Commendably, the architects at BGP Arquitectura have made the Castro Leal Library all about the books.