J. Casares is the first modern Spanish phraseologist, being his classification of the idioms (see three chapter of the Introducción a la Lexicografía moderna, from 1950) the starting point of later studies by this topic. Likewise, as RAE Lexicography Seminar director (1947- 1964), his phraseological concepcion was moulded, to a great extent, in DRAE as soon in the Diccionario histórico. These facts justify the dedication of a monografic work to J. Casares, an advanced linguistic of his time in relation with phraseology and others linguistic disciplines.