Since the publication of the still very valuable Biblioteca histórica de la filología by Cipriano Muñoz y Manzano, conde de la Viñaza (Madrid, 1893), our knowledge of the history of the study of the Spanish language has grown considerably, and most manuscript and secondary sources had never been tapped before Hans-Josef Niederehe of the University of Trier courageously undertook the task to bring together any available bibliographical information together with much more recent research findings, scattered in libraries, journals and other places. The resulting Bibliografía cronológica de la lingüística, la gramática y la lexicografía del español: Desde los principios hasta el año 1600 (BICRES) began appearing in 1994. BICRES I covered the period from the early beginnings to 1600, followed by BICRES II (1601-1700), BICRES III (1701-1800), and together with Miguel Ángel Esparza Torres of Madrid there followed BICRES IV (1801 to 1860). Now, the fifth volume, has become available, covering the years from 1861 to 1899. Access to the bibliographical information of altogether 5,272 titles is facilitated by several detailed indexes, such as a short title index, a listing of printers, publishers and places of production, and an author index.
More than twenty years of research in the major libraries of Spain and other European countries have gone into this unique work — relative sources of the Americas have also been covered — making it exhaustive source for any serious scholar of any possible aspect of the Spanish language.