The two volumes of A Lexicon of the Romaunt of the Rose are a sequel to, and a development of, A Lexical Concordance to the Works of Geoffrey Chaucer in two volumes in five parts which were published in 2003-2004. The Lexicon is the third and final milestone on a long road. Its goal is a comprehensive dictionary of the language of Geoffrey Chaucer. The first milestone, A Complete Concordance to the Works of Geoffrey Chaucer in ten volumes, appeared in 1991-1992. A Concordance to the Romaunt of the Rose which was published in 1991 is the ninth volume of the unlemmatized Complete Concordance. 'A lexicon of the 'Romaunt of the Rose'', which is designed to function as both a concordance and a dictionary, is a systematic investigation into the lexical and grammatical items in the Middle English translation of the 'Roman de la Rose' of Guillaume de Lorris and Jean de Meun. The 'Lexicon' gives ample references to the Old French source.