This book contains information on Mayan cycles of the calendar, history, gods and spirits, weather, and astronomy.
A coating of fine white lime is applied to both sides of the paper sheets (made from a pulp made from the fig tree) to provide a smooth finish upon which to paint. The hieroglyphs are painted on both sides so to read them you would read along one side of the paper strip, from left to right, and then turn the book over and read the other side.
(text description edited from Northwestern University.)
Artist: Mayan. (Paris Codex).
More information online here, thanks to Northwestern University.