Marvel's first real foray into digests didn't star Spider-Man, Hulk, the X-Men, or any other staple of the House of Ideas, but Dennis the Menace!
Dennis had just received his own monthly title from Marvel a few month earlier, and I guess the initial sales were strong enough for them to give the little tyke a second title. Unfortunately, neither Dennis title lasted too long--the monthly regular book ended with #13, and this digest only ran three issues.
As a kid, I never gave a second thought to Dennis the Menace as a comic strip--I didn't think it was funny and the art did nothing for me. But as I've gotten older, I've come to really appreciate Hank Ketchum's beautiful linework and sense of design. And while I still don't think Dennis is funny, looking at the strips themselves is a joy to behold.
These Dennis stories though are not strip reprints--they're long-form comic book stories that are(as far as I know) original, either done by Ketchum or(more likely) a stable of assistants and ghost artists. The stories included are: "Tag-Along Trouble", "Dennis the Golfer", "The Kitty Catchers", "All Gummed Up", "The Amazement Park", "The Compact Car Caper", "Always a Lady", "Cake Walk", "The Dog Snatchers", "A Case of School-itis", "Dennis the Salesman", and "Dennis Vs. The Zoo."
This first issue even has a one-page Margaret strip and a "How to Draw Dennis' Dad" feature page, making for a fun package.
Update: As DigestFan Craig Wichman pointed out in the comments section, what the heck is a DC plug doing on the UPC code of a Marvel comic? I can't believe I missed that!