The title of "Vitruvii De Architectura" is an acronym that anticipates to us on the subject of ten books: the main rules of the architecture.
It’s "VITRVVII" the treaty on architecture written by the three times master. That architect could not be another one in the first century B.C. Marco Agrippa.
The autor wrote the precepts of architecture in "cybicis rationibus". "De Architectura" containing three six number. Its readers may read and understand as much as possible in few free moments. LiberV-Praefatio