A page is half the span of a book (from edge to center). A sheet is the full span of the book (from edge to edge). One sheet equals two pages. The Flush Mount Albums start at 16 pages (8 sheets) and the Press Photo Book and Layflat Photo Books start at 20 pages (10 sheets). Additional pages are sold in increments of two because we cannot bind uneven page amounts. Therefore the price listing on our product pages is for one page, but pages must be purchased in increments of two.