Alypius of Alexandria (Greek: Ἀλύπιος) was a Greek writer on music who flourished c. 360. Of his works, only a small fragment has been preserved, under the title of Introduction to Music (Εἰσαγωγὴ Μουσική).
The work of Alypius consists wholly, with the exception of a short introduction, of lists of the symbols used (both for voice and instrument) to denote all the sounds in the forty-five scales produced by taking each of the fifteen modes in the three genera (diatonic, chromatic, enharmonic). It treats, therefore, in fact, of only one (the fifth, namely) of the seven branches into which the subject is, as usual, divided in the introduction; and may possibly be merely a fragment of a larger work. It would have been most valuable if any considerable number of examples had been left us if the actual use of the system of notation described in it; unfortunately very few remain, and they seem to belong to an earlier stage of the science. However, Alypius's work remains the best source of modern knowledge of the musical notes of the Greeks, including a comprehensive account of the Greek system of scales, transpositions, and musical notation, and serves to throw some light on the obscure history of the modes.
The text, which seemed hopelessly corrupt to its first contemporary editor, classical scholar Johannes Meursius, was nevertheless restored, apparently with success, by the Danish scholar Marcus Meibomius.Introduction to Music was printed with the tables of notation in Meibomius' Antiquae Musicae Scriptores, (in quarto, Amsterdam 1652). Meibomius not only made use of the manuscript belonging to Joseph Scaliger, but others also existing in England and Italy. Karl von Jan published an authoritative edition in Musici Scriptores Graeci, 1895-1899.