The encyclopedia by Alberto and Arturo Garcia Carraffa "Dicionario
Heraldico y Genealogico de Apellidos Espanoles y Americanos" is reknown
as the bible of spanish surnames. The listing given inforamtion as to
the locations where surnames originated, coats of arms and brief
genealogical lineages. The Library of Congress's Hispanic Reading Room
has compiled a searchable index so that you can search for your surname
and find which volume contains it. It also lists the few US libraries
which have a copy of this encyclopedia. However, if you do not have
access to these, the LDS church has microfilmed the entire work. The
Cubagenweb site has a listing of the microfilm numbers and the
correlation to the volumes for ease of ordering films at LDS family
history centers. The encyclopedia is in spanish but is easily
translated.
