In 1806, the United States was on the brink of war with Spain over the disputed western boundary of the Louisiana Purchase and anticipated invading New Mexico. Possessing only meager information on the terrain as well as Spanish troop numbers and fortifications, President Thomas Jefferson and General James Wilkinson needed an agent who could cross the continent to Spanish territory all the way to the capital of Santa Fe, provide a plausible "cover story" for being there, and returban with the vital information. is the story of how Pike carried out his mission as a prelude to an American invasion of New Mexico. This unique book is the first to fully chronicle Pike's 1806–1807 expedition to the Rocky Mountains and beyond, addressing both the exploratory and the clandestine purposes of Pike's western jourbaney. By carefully examining the evidence available in primary documents, which shows that Pike prepared and carried a map showing a route to Santa Fe on his jourbaney, the author overturbans the conventional wisdom that Pike became lost searching for the Red River and mistakenly wandered into Spanish territory. This book also presents the Spanish perspective and response to Pike's invasion of Spanish territory and provides historical context to understand the role of Pike's expedition in Thomas Jefferson's quest to build an American "empire for liberty."