Some effort has been made to bring before the scholarly world and the interested public certain of the outstanding accounts of expeditions and explorations. The period of 1765 to 1776 has been very adequately covered, particularly by the late Professor Herbert E. Bolton, who is remembered for his editing of the diaries of Crespi, Portola, Anza, and others. The later exploration has been the subject of a few works, such as Gayton's translation of the Estudillo manuscripts. Both Herbert I. Priestley and Donald C. Cutter have contributed to our body of knowledge of the time. Priestley's little book on the Franciscan explorations, finished after his death by Lillian E. Fisher, is a rather brief general description of the expeditions to the Central Valley. Cutter's exhaustive thesis (1950) is a very satisfactory exposition of Central Valley exploration from the standpoint of the Spanish-Mexican colonial policy and missionization. Cutter, however, merely paraphrases and condenses the actual documents, thereby omitting much of the detail to be found in the original accounts. Neither Priestley nor Cutter concerns himself with Indian relations or explorations in Southern California and on the Colorado River, nor do they carry their consideration of the Central Valley past 1820. For a complete picture, therefore, the student of the early nineteenth century must seek out the primary documents. The written records within the area under discussion are deposited in a very few libraries and archives and, moreover, the documents, with the exceptions noted, are in handwritten Spanish. For these reasons a valuable body of information can be reached only with relative difficulty by students at large. Thus it seems worth while to assemble this material, translate it into English, and disseminate it in printed form among institutions of learning and research. At the same time a certain minimum amount of editorial organization is necessary, together with some explanation and commentary. The present group of translations embodies all the pertinent documents I can find dealing with the Central Valley of California in the period from 1800 to 1820. Not all the possible correlated references are included. The emphasis is upon the actual progress of exploration and physical contact with the natives--from the point of view of the natives. Consequently, no attempt is made to include papers bearing solely on political background, personal biography of participants, detailed military or logistic preparations, controversies between military, civilian, and ecclesiastical interests, and matters of official policy. For the broad historical setting and the details of organization the works of Bancroft, Bolton, Priestley, and Cutter will be found entirely adequate.