"Antonio de Torres: Guitar Maker - His Life and Work."  by José L. Romanillos
This meticulously researched book by J. Romanillos is divided into two parts. The first relates the life of Torres (1817-92) in Seville and Almeria; the second one deals with the more technical aspects of his instruments: his method of guitar construction, the plantillas he used, types of wood, the inlays, and his use of the tornavoz.
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"Master Guitars." by Roy Courtnall
An essential text for aspiring makers. Part 1 consists of eight chapters: each one devoted to a master luthier. Beginning with A. Torres, the author continues with S. Hernández,  H. Hauser, Hernández y Aguado, I. Fleta, R. Bouchet, D. Friederich and ends with José Romanillos. In addition to an interesting short biography of each maker, there are in-depth plans, rosette illustrations, and other interesting details of the maker’s instruments. Parts 2 and 3 describe the tools, materials, and procedures of the Spanish school of guitar construction. 
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"A Collection of Fine Spanish Guitars from Torres to the Present." by Sheldon Urlik 
This book presents one of the world's finest collections of modern and contemporary Spanish Guitars. Over 65 classical and flamenco guitars are presented with documentation, technical information and insights into their historical significance. Makers represented include among others: A. Torres, M. Ramirez, S. Hernandez, D. Esteso, M. Rodriguez, H. Hauser, J. Romanillos, G. Smallman, J. Gilbert, T. Humphrey, P. Bernabé.
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"Things About The Guitar." by José Ramirez III
A collection of highly informative articles on the family dynasty and on numerous aspects of guitar making, based on his personal experiences of over 30 years of classical guitar building at the top of the profession. Written in Ramirez's inimitable droll prose style. Highly recommended.