We trust it will not be regarded as presumptuous if we say a word in relation to the facilities we have enjoyed and the methods we have used in the preparation of this work. We knew Mr. Lincoln intimately before his election to the Presidency. We came from Illinois to Washington with him, and remained at his side and in his service-- separately or together--until the day of his death. We were the daily and nightly witnesses of the incidents, the anxieties, the fears, and the hopes which pervaded the Executive Mansion and the National Capital. The President's correspondence, both official and private, passed through our hands; he gave us his full confidence. We had personal acquaintance and daily official intercourse with Cabinet Officers, Members of Congress, Governors, and Military and Naval Officers of all grades, whose affairs brought them to the White House. It was during these years of the war that we formed the design of writing this history and began to prepare for it. President Lincoln gave it his sanction and promised his cordial cooperation. After several years' residence in Europe, we returned to this country and began the execution of our long-cherished plan. Mr. Robert T. Lincoln gave into our keeping all the official and private papers and manuscripts in his possession, to which we have added all the material we could acquire by industry or by purchase. It is with the advantage, therefore, of a wide personal acquaintance with all the leading participants of the war, and of perfect familiarity with the manuscript material, and also with the assistance of the vast bulk of printed records and treatises which have accumulated since 1865, that we have prosecuted this work to its close.