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

pictorial wraps : Indicates that the covers of a paperback are decorated with a pitcure of some sort.

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.