It is as fascinating as it is mysterious - the complex calendar of the ancient Maya. The analyses of the corresponding hieroglyphs from inscriptions and codices reveal to us the structure and functioning of perhaps the cleverest timekeeping system in human history. The path to understanding involves brilliant mathematics, astonishing astronomical insights, and touches upon a mythology that seems exotic to us. Authors Rohark and Krygier present the content in a structured manner through entertaining lectures and seminars using exclusive material. In addition to many drawings of real inscriptions, they created a complete imaginary inscription, a calculation codex suitable for performing all operations of calendar mathematics, as well as software for date calculations and for observing astronomical events of the classical period.