The outlines of classification may be found in the Table of Contents to each volume, and a brief synopsis of generic, family, and ordinal characters, in the Analytical Key prepared by Professor Jones. It has not been thought best to give large place to these matters nor to intrude them upon the text, because of the many excellent manuals which already exist giving especial attention to this field. The nomenclature is chiefly that of the A. O. U. Check-List, Second Edition, revised to include the Fourteenth Supplement, to which reference is made by number. Departures have in a few instances been made, changes sanctioned by Ridgway or Coues, or justified by a consideration of local material. It is, of course, unfortunate that the publication of the Third Edition of the A. O. U. Check-List has been so long delayed, insomuch that it is not even yet available. On this account it has not been deemed worth while to provide in these volumes a separate check-list, based on the A. O. U. order, as had been intended. Care has been exercised in the selection of the English or vernacular names of the birds, to offer those which on the whole seem best fitted to survive locally. Unnecessary departures from eastern usage have been avoided, and the changes made have been carefully considered. As matter of fact, the English nomenclature has of late been much more stable than the Latin. For instance, no one has any difficulty in tracing the Western Winter Wren thru the literature of the past half century; but the bird referred to has, within the last decade, posed successively under the following scientific names: _Troglodytes hiemalis pacificus_, _Anorthura h. p._, _Olbiorchilus h. p._, and _Nannus h. p._, and these with the sanction of the A. O. U. Committee—certainly a striking example of how _not_ to secure stability in nomenclature. With such an example before us we may perhaps be pardoned for having in instances failed to note the latest discovery of the name-hunter, but we have humbly tried to follow our agile leaders.