In this book, William Foster produces the first highly accurate maps of the eleven Spanish expeditions that passed overland from northeastern Mexico into what is now East Texas during the nearly eighty years between 1689 and 1768.

Foster draws upon the detailed diaries that each expedition kept of its route, rigorously cross-checking the journals among themselves and against previously unused eighteenth-century Spanish maps, modern detailed topographic maps, aerial photographs, and on-site inspections. From these sources emerges a clear picture of where the Spanish explorers actually passed through Texas.

This information, which corrects many previous misinterpretations of the Spanish routes, will be widely valuable. Old names of rivers and landforms will be of interest to geographers. Anthropologists and archaeologists will find new information on encounters with some 140 named Indian tribes. Botanists and zoologists will see changes in the distribution of flora and fauna with increasing European habitation, and climatologists will learn more about the "Little Ice Age" along the Rio Grande.