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

Mass market paperback : Also known as the pocket paperback. A small format paperback usually measuring about 4" by 6".

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.

Fair : is a worn book that has complete text pages (including those with maps or plates) but may lack endpapers, half-title, etc. (which must be noted). Binding, jacket (if any), etc., may also be worn. All defects must be noted. (defined by AB Bookman's Weekly)