The Greek Grammar by Constantinus Lascaris (Κωνσταντῖνος Λάσκαρις) is perhaps the oldest printed work in Greek, dating from 1476.
Two questions. . .
I read through this work, once as an undergraduate and once later, but can't recall seeing any indication as to what Lascaris' own sources were. It is too comprehensive and systematic to have been written ad hoc, and even if it were from memory, it would need a model for organisation. ...