here and here, along with partially inked sample images that may have a touch of Ditko's then studio-mate Eric Stanton as well.
Dell's comics at the time were pretty generous with the page count, with very few ads (the backcover and a half-page interior), so even with the photo cover you get 34 pages of Ditko artwork in here. The interior front and back covers are a nice treat, both with single page black and white stories that are the highlights of the book, "Self Defeat" and "Hot Wire", which look really nice on the better printed glossy paper stock, and are nice cute gags that are in keeping with the show (for the record, I was a big fan of the show as a kid, though it's been over a decade since I've seen it).
The interior story is one long 32-page adventure divided into three chapters, "The Dumb Dummy" (12-pages), "Dungeon Of Doom" (11-pages) and "Double Trouble" (9-pages). It really doesn't make a lot of sense, but involves a Kaos agent creating robot doubles of people and some such. Doesn't really capture the show at all, and has some really odd bits (for some reason the Chief is called Control half the time, which I don't recall from the show).
The art is pretty snappy, though. Not quite up to most of the other stuff Ditko was up to in 1966, but getting the job done with some nice flourishes (a few nice double-takes and weird expressions, and of course those Ditko fingers). The likenesses aren't too great, with Maxwell Smart being almost unrecognizable except for a few panels, and the Chief way off. Agent 99 was closer to model, and at least generally consistent.
Can't really recommend this with so many other pure Ditko things out there, but if you ever run out of those you might want to pick this up. Has anyone read Ditko's HOGAN'S HEROES issues? Worth a look?