Such was the origin of the present work, now happily brought to a close after a period of six years, during which it has occupied no unimportant part of my leisure time. Even so it would not have been possible for me to have accomplished it without the able assistance of my excellent friend Mr. Oldfield Thomas, of the British Museum. It was, of course, of the greatest advantage to the work that Thomas was already familiarly acquainted with the subject, and had, moreover, under his charge the unrivalled series of specimens of Mammals contained in our National Collection. Although Thomas and I consider ourselves, of course, jointly responsible for all the statements in this work, every line of which has undergone the supervision of both authors, I may state that Thomas’s chief part of the task was, as agreed between us, to be the synonymy and scientific descriptions, and my speciality the preparation of the ordinary letterpress. I must also not omit to mention that as regards the much-vexed subject of Zoological Nomenclature my friend and I are not in perfect accord, as he takes a more severe view of the rule of priority than I am disposed to adopt. There has, therefore, been necessarily a little “give and take” on each side as to the names to be adopted in this work. For these latter, in so far as they may be held to contravene the strict laws of nomenclature, Thomas desires to disclaim--as I am willing to accept--all responsibility. It should also be mentioned that during the issue of the last volume Thomas’s somewhat serious illness and consequent absence from his post in London has compelled him to relegate some of his share in the present work to Mr. R. I. Pocock, of the British Museum, who, I need hardly say, has most efficiently assisted me in finishing the task and to whom I hereby tender my most sincere thanks. I must also not forget to record the names of other friends and correspondents who have materially assisted us in the preparation of the ‘Book of Antelopes.’ Amongst these I must specially mention Herr Matschie, of the Natural History Museum of Berlin, who has kindly furnished many notes on the collection of Mammals under his charge in that Institution; nor must I forget the names of Mr. F. C. Selous, Herr Oscar Neumann, Mr. S. L. Hinde, Mr. F. V. Kirby, Capt. H. G. C. Swayne, Mr. Ernest Gedge, Sir Harry Johnston, K.C.B., Mr. R. Crawshay, Mr. Alfred Sharpe, Sir John Kirk, Mr. F. E. Blaauw, Mr. F. J. Jackson, Major F. C. Trollope, Dr. E. Büchner, Mr. E. Buxton, Mr. J. I. S. Whitaker, Sir Edmund Loder, Mr. A. E. Pease, Mr. Lort Phillips, Mr. T. W. H. Clarke, Mr. J. ffolliott Darling, Mr. John Millais, Mr. W. E. de Winton, and my son Mr. W. L. Sclater, Director of the South African Museum, Capetown, to all of whom, on behalf of Thomas and myself, I wish to tender our most heartfelt thanks for their kind assistance. Finally, I may mention that this work has been issued in parts at the following dates:--