wraps : The paper covering on the outside of a paperback.

12mo : An abbreviation for duodecimo, a book size describing a book which is approximately 7 by 4.5 inches.

first thus : Indicates that this is not the first appearance of a book in print, but that this is the first appearance in a substantially different format than the true first edition. For example, a first illustrated edition of a book, or even a first paperback release of a book originally published in hard cover.