The large extant body of manuscripts that did survive can now be found in museums, archives, and private collections. There has been considerable scholarly work on individual codices as well as the daunting task of classification and description. A major publication project by scholars of Mesoamerican ethnohistory was brought to fruition in the 1970s: volume 14 of the "Handbook of Middle American Indians, Guide to Ethnohistorical Sources: Part Three" is devoted to Middle American pictorial manuscripts, including numerous reproductions of single pages of important pictorials. This volume includes John B. Glass and Donald Robertson's survey and catalogue of Mesoamerican pictorials, comprising 434 entries, of which a considerable part procede from the Valley of Mexico.