For more than a quarter of a century J. Eric S. Thompson has been investigating the Maya: he has made ten field trips of excavation and exploration in Central America.  An archaeologist with the Carnegie Institution of Washington since 1935, Mr. Thompson is especially known for his work on Maya hieroglyphic writing.  He is author of a number of other books and many articles in the field.  this volume, which embodies the most important results of the work of the Department of Historical Research, Carnegie Institution of Washington, in the Maya area for the past twenty-five years, was written because Mr. Thompson felt the need of an accurate account of the Maya which also tried to explain their civilization.