The Maya are the only Mesoamerican people whose own writing can be read at length, and that changed the field completely within living memory.
Four screenfold books survived the colonial burnings, of which the Dresden Codex is the most complete: astronomical tables, almanacs and ritual sequences, not narrative. The Popol Vuh is a different kind of survival, a K'iche' account written down in the Latin alphabet in the sixteenth century and copied in the eighteenth, and it is the fullest creation narrative from anywhere in the Americas. It is also post-conquest, written by people who had encountered Christianity, and arguments about how much that shaped it are ongoing.
The transforming development is the decipherment of the hieroglyphic script, achieved over the second half of the twentieth century after a long period in which the writing was believed to record only calendar and astronomy. It is now read as language, and the monumental inscriptions turn out to be substantially historical: named rulers, dated accessions, wars, and the ritual acts by which kings dealt with gods. Statements about Maya religion made before that work are frequently obsolete.
The Books of Chilam Balam add a colonial-period Yucatec layer, prophetic and historical and heavily mixed.
None of this is a dead subject. The 260-day count is still kept by day-keepers in the Guatemalan highlands, and the tradition has living custodians whose practice is theirs rather than the atlas's to describe.