Citizens who thus devote themselves to the advancement of science and intellectual cultivation in their country,—whose exertions tend so immediately to elevate it in the scale of civilization and refinement, deserve to be ranked with its most illustrious scholars, statesmen, and soldiers, and are equally entitled to the national gratitude. So long as the condition of, or progress in the arts and sciences shall continue to characterize nations, the influence in the United States of the gentlemen to whom we have alluded, must be regarded as important in the highest degree, and their services will be gratefully remembered by their countrymen so long as the sciences are cultivated or appreciated. They have reared in their native city a monument to Natural Science as endurable as its influence in the minds of men, and more honorable to themselves than the proudest obelisk or the richest memento of the conqueror’s triumph. With such facilities for study, we have necessarily had advantages over other American Ornithologists. One object of our work is to present a general revision of the Ornithology of the United States, endeavoring to bring our subject nearer to the true state of the science than has been previously attempted in this country. In our Synopsis, the student will find many corrections and additions, and will find himself, too, very probably introduced to names both American and European, of the connection of which with North American Ornithology, previous records are silent, quite unjustifiably. Our predecessors have not been well versed in the history and bibliography of Ornithology, nor indeed have they professed such information. It is in fact a description of knowledge to be attained with difficulty in any country,—so great, indeed, that no one Ornithologist has ever yet been completely acquainted with the bibliography of his science. To our publishers, Messrs. J. B. Lippincott & Co., is due our gratitude for constant kindness and encouragement during the publication of the present volume. Our treatment by the members of this eminent firm has in fact most fully demonstrated to us their deep interest in the Natural Sciences, as gentlemen of taste and cultivation, quite irrespective, so far as relates to our work, of merely business considerations. To the kind friends whose contributions have added so much to the interest of this volume, we have to express our sense of great obligation, especially to Col. George A. McCall, Capt. J. P. McCown, Capt. S. G. French, Dr. T. C. Henry, of the U. S. Army, to Mr. John G. Bell, Dr. A. L. Heermann, Dr. P. R. Hoy, Dr. S. W. Woodhouse, Mr. John H. Clark, Dr. Charles Pickering, and Dr. C. B. R. Kennerly. To Dr. A. Hall, of Montreal, and Dr. R. Haymond, of Brookville, Indiana, for much valuable information relating to the birds of their districts.