The true student of history, when confronted for the first time with a statement of what purports to be an historical fact, weighs at the outset, as all-important, the evidence of its accuracy. If there be at hand no means of verifying the statement, the only ground of assurance is a knowledge of who is speaking, how likely he is to know the truth, and how well fitted he is to tell it; for to be a writer of accurate history one must not only know facts, but must also be truthful, and so far above bias upon his subject as to be able to treat it fairly, openly, and without false coloring of any part. It is therefore the first canon of historical criticism to accept as authority no statement unless it be known who is making that statement. The greater our interest in a given subject, the more important to us becomes the question of the authority for all statements concerning that subject. As the field of history is narrowed down to a single state or to a single locality, where every man may to a certain extent be an historian, an anonymous written account, though excellent in itself, will still be viewed with suspicion. The fact that there is a good local knowledge of the subject by no means removes the necessity of determining authorship. Fortunate it is for the Pacific States and Territories of the United States that data concerning their history from its beginning were collected during the lifetime of men who laid the foundations of these commonwealths. It is then a matter of the highest importance to the people of this vast empire to know who wove this material together, and wrote the only attempt at a full and connected history of the Pacific Coast which has ever been published. The completion of the Bancroft series of Pacific Slope histories, to which reference is here made, marks an event unique in the annals of history writing. At no other time and in no other land has there been carried to completion a work of like character and magnitude. There had previously been written a few histories of Oregon and California covering a certain period, and designed chiefly to give a treatment of a certain institution or political subject, but so far as the thorough working up of the whole ground was concerned, a virgin field presented itself.