This series was published by iBooks and contains reprints of the original MAD paperbacks written in the 1950s by the usual gang of idiots. All paperbacks of this series measures a size of 5 x 0.5 x 8 inches and have around 206 pages.
A group of several U.S. paperback collectors have determined that iBooks printed only a single cover for all printings of the "Anniversary" paperbacks. Five of the books say 50th Anniversary on them: Bedside, Inside, MAD Reader, Strikes Back, and Utterly. The other four books--Fighting, Ides, Organization, and Son of--say Anniversary Edition.
While MADtrash.com is correct in showing two different spines on the MAD Reader, most of the paperback collectors have determined that very slight changes made with respect to the placement of logos and prices are not to be included as cover variants. (Moving the price information from the top to the side of the front cover was commonly done by Signet and, although less commonly, by Warner.)
Either iBooks, which were distributed through Simon & Schuster, questioned whether there was a sufficient market for these books or whether they sold beyond expectations. Either way, it appears the books were printed in short runs. It's really tough to find 1st prints (some of these went to at least 3rd printings).
According to Joe Cunningham (who should be credited with obtaining the initial information), S&S transferred distribution rights to Publisher's Group West. PGW allowed the reps to choose any title they thought they could sell for reprinting. Therefore, it is unknown which titles were actually printed. I'm not sure these books are not just untrimmed versions of the iBooks versions, since, even though these books are a half inch taller than the iBooks versions, the interior artwork is the same size as the original iBooks versions.
The iBooks ISBNs start with 7434, while the PGW books start with 5968. We have collectively decided not to include the 5968 books in a count of known paperbacks.