This is a very helpful post on understanding the way pages are numbered in some early modern books (something I’ve had to pick up on my own). Some are numbered like modern pages: 1, 2, 3 and so on. Others are numbered by column, with two to a page. Many are folio-volumes, meaning they are numbered every other page: 1, blank, 2, blank and so on. These are referenced as fol. 1r (for recto, the front or ‘right’ side), fol. 1v (for verso, the back side), fol. 2r and so on. Others, like those spoken of in this post, have a much more confusing numbering system: A i, blank, A ii, blank and so on … then B i, blank, B ii, blank and so on. The author explains in much helpful detail with examples, pictures and some interesting details.