Gonzalo Correas (c.l570–1631) publishes his Ortografìa Kastellana in 1630. In this proposal at an orthographic reform of Spanish Correas refers regularly to Antonio de Nebrija’s (1444–1522) Gramatica castellana (1492), on the one hand, and Mateo Aleman’s Ortografia castellana (1609), on the other. Although he shows a certain respect for his predecessors, Correas does not fail to note a lack of rigour and ambiguities resulting from this lack. He strives for more precision than his predecessors who had limited their analysis to merely descriptive phonetic detail, he clearly departs from the Latin tradition, and rejects the etymological approach to orthography. Correas starts off with an analysis of the phonological system of the language of his time in order to propose an orthography that is both coherent and transparent, something which also signals his pedagogical concerns. In order to arrive at a one-to-one correspondence between pronunciation and graphic representation, he does not spare any effort to find an adequate sign system. He proposes altogether 25 letters to represent the 25 types of sound he had identified, fully in accordance with the economy principle which requires that one sign represents one and only one type of sound and vice versa. This alphabetical system constitutes an adaptation of the already existing alphabet. During a generally precise and rigorous discussion Correas justifies the suppression of certain redundant signs, the use of certain letters with new values, and the introduction of ligatures. On the other hand, he undertakes the elaboration of a new alphabetical order divested of any arbitrariness by establishing a hierarchy of letters in which distributional criteria play a primordial role. In effect, if abstraction is made of certain debatable points, the argument as a whole is coherent and rigorous, to the extent that it could be said that his proposals, if adopted, could have improved considerably Spanish orthography. The elaboration of his alphabetical system makes him a theorist of considerable stature.