Spanish naming customs
Spanish names are the traditional way of identifying, and the official way of registering, a person in Spain. They comprise a given name (simple or composite) and two surnames (the first surname of each parent). Traditionally, the first surname is the father's first surname, and the second is the mother's. Since 1999, the order of the surnames in a family is decided when registering the first child, but the traditional order is nearly universally chosen (99.53% of the time).
The practice is to use one given name and the first surname generally (e.g. "Miguel de Unamuno" for Miguel de Unamuno y Jugo); the complete name is reserved for legal, formal and documentary matters. Both surnames are sometimes systematically used when the first surname is very common (e.g., Federico García Lorca, Pablo Ruiz Picasso or José Luis Rodríguez Zapatero) to get a more distinguishable name. In these cases, it is even common to use only the second surname, as in "Lorca", "Picasso" or "Zapatero". This does not affect alphabetization: "Lorca", the Spanish poet, must be alphabetized in an index under "García Lorca", not "Lorca" or "García".