Calle Bravo Murillo, 85
Librerķa Calatrava, the oldest bookshop in Madrid, contains an endless source of fascinating literature. It was founded by the protestant cleric Federico Fliedner, and was initially known as Librerķa Nacional y Extranjera (National and Foreign Library).
Specializing in the protestant religion since its beginnings in 1873, today it offers a wide range of books on all religions and various other topics. The staff is noted to have an extensive knowledge of local authors as well.