In the twenty-odd books known to have been autographed by the dramatist, the signature is commonly “Will: Congreve,” but the surname is sometimes preceded by “W,” “Wm,” “Willm,” “Gul,” “Gulielmi,” or “Gulielmus.” One of Congreve’s books (Number 236 in the list) preserved in the Yale Library uses both “W: Congreve” and “Gulielmus Congreve” in different signatures. None of the signatures should be accepted as that of the dramatist until the handwriting is verified, for “William” has long been a common Christian name in the Congreve family. In 1700 there were living no fewer than five Congreves bearing this name, all descended from the same grandfather. One of these was Colonel William Congreve (1671-1746) of Highgate, a cousin of the dramatist, whose papers have been confused with those of the dramatist in many sales as well as in many American libraries. The colonel usually signed “Will:” as did the dramatist, but the two cousins formed the “W” in strikingly different ways. The colonel rounded the first upper prong of this letter and brought the middle prong to only little more than half the height of the other prongs; the dramatist sharpened the first prong and brought the middle prong fully up to the height of the others. Since the present Duke of Leeds reports that he no longer has books bearing Congreve’s signature, we may presume that they were largely, if not fully, disposed of in the two sales of 1930 and are now widely scattered. Books with Congreve’s signature are preserved at the Yale Library (Congreve’s Numbers 236, 262, 441), at the Library of the University of Tennessee (Numbers 119, 595), at the Morgan Library (Number 289), at the Boston Public Library (Number 192), at the Brotherton Library of the University of Leeds (Number 541), and in the private libraries of E. S. de Beer, Esq., (Number 518) and the Reverend J. F. Gerrard (Number 371). The editor of this work will be grateful for information concerning the location of other volumes bearing the true signature of William Congreve (1670-1729). Such volumes will be doubly interesting if annotated in the dramatist’s handwriting. Some of the books were thus annotated, according to Jacob Tonson, in his letter of 27 January 1728/29 (a few days after Congreve’s death), to his nephew, Jacob Tonson, Junior: “His [Congreve’s] collection of Books were very genteel & well chosen. I wish you should think them worth your buying; I think there are in [these] books several notes of his own or corrections & everything from him will be very valuable.” _Editing and Printing the Book List_