If one proposes to write a history of the times of Abraham Lincoln, how shall one begin, and how proceed? Obviously, the first thing needed is information, and as much of it as can be had. But how shall information, accurate and trustworthy, be obtained? Of course there are plenty of books on Lincoln, and histories enough covering the period of his career to fill shelf upon shelf. It would be quite possible to spread some dozens of these before one's self and, drawing simply from them, work out a history that would read well and perhaps have a wide sale. And such a book might conceivably be worth while. But if you were reading it, and were a bit disposed to query into the accuracy of the statements made, you would probably find yourself wondering before long just where the writer got his authority for this or that assertion; and if, in foot-note or appendix, he should seem to satisfy your curiosity by citing some other biography or history, you would be quite justified in feeling that, after all, your inquiry remained unanswered,--for whence did this second writer get _his_ authority? If you were thus persistent you would probably get hold of the volume referred to and verify, as we say, the statements of fact or opinion attributed to it. When you came upon them you might find it there stated that the point in question is clearly established from certain of Lincoln's own letters or speeches, which are thereupon cited, and perhaps quoted in part. At last you would be satisfied that the thing must very probably be true, for there you would have the words of Lincoln himself upon it; or, on the other hand, you might discover that your first writer had merely adopted an opinion of somebody else which did not have behind it the warrant of any first-hand authority. In either case you might well wonder why, instead of using and referring only to books of other later authors like himself, he did not go directly to Lincoln's own works, get his facts from them, and give authority for his statements at first hand. And if you pushed the matter farther it would very soon occur to you that there are some books on Lincoln and his period which are not carefully written, and therefore not trustworthy, and that your author may very well have used some of these, falling blindly into their errors and at times wholly escaping the correct interpretation of things which could be had, in incontrovertible form, from Lincoln's own pen, or from the testimony of his contemporaries. In other words, you would begin to distrust him because he had failed to go to the "sources" for his materials, or at least for a verification of them. [Sidenote: The superiority of direct sources of knowledge]