In classical scholarship, editio princeps is a term of art. It means, roughly, the first printed edition of a work, that previously had existed only in manuscripts, which were therefore circulated only after being copied by hand.
For example, the editio princeps of Homer is that of Demetrius Chalcondyles, now thought to be from 1488. The most important texts of classical Greek and Roman authors were for the most part produced in editio princeps in the years on either side of 1500.
The picture is complicated by the possibilities of partial publication, of publication first in translation (for example from Greek to Latin), and of a usage that simply equates with first edition. For a work, such as Piers Plowman, with several strands of manuscript tradition that have diverged, it is a less meaningful concept.
The term has long been extended by scholars to works not part of the Ancient Greek and Latin literatures. It is also used for legal works, and other significant documents.
Promis, however, published only six of the seven books. The last book which deals with all kinds of mechanical devices was omitted and subsequently escaped the notice of historians of technology for the next hundred years.[6]
^ Ladislao Reti, “Francesco di Giorgio Martini's Treatise on Engineering and Its Plagiarists”, Technology and Culture, Vol. 4, No. 3. (Summer, 1963), pp. 287-298 (288)
