"In April 1780 Military Governor Ugarte and Chief Engineer Rocha were sent on reconnaissance through the northwestern frontier of New Spain, land that today is northern Sonora and southeastern Arizona. Toward the end of the 1500-mile journey, Rocha's mule tumbled down a river slope and his papers, books, and the rest he had with him went down with it. He salvaged what he could of these materials, including the diary on which this current book is based. Seeking information on the advisability of placing a presidio at the junction of the San Pedro and Gila rivers, Ugarte and Rocha described the landscape in unprecedented detail. Their accounts provide valuable baseline information on environment and culture that allow analysis of changes occurring at this critical moment in borderland history. The translations of their orders, summary reports, journal, and map provided in this volume are interwoven and informed by a variety of sources (ethnography, borderland history, ethnohistory, oral history, and archaeology) that collectively draw out the significance of these documents, enriching the content and providing a glimpse into the harsh realities and intrinsic beauty of the region. Deni Seymour's more than 30 years of experience studying the Colonial period in this very part of the Southwest lends depth and perspective to the narrative"--Provided by publisher.