The Mayan Secrets - Clive Cussler, Thomas Perry

Husband and wife team Sam and Remi fargo are in Mexico, when they come upon an astonishing discovery the skeleton of a man clutching an ancient sealed pot, and within the pot, a Mayan book, larger than anyone has ever seen. The book contains astonishing information about the Mayans, their cities and about mankind itself. The secrets are so powerful that some would do anything to possess them- as the Fargos are about to find out. Before their adventures is done, many people will die for that book- and Sam and Remi may just be among them.