I have not a clue about the Matt Helm books, but it kind of sounds familiar.
I do know who Dean Martin is, though. If that counts for anything.
I think part of the problem is the level of initial exposure versus long-term recognition - some characters get brought back constantly (Sherlock Holmes, for example), while others slink off into the shadows (and most of them deserve it, if I am being brutally honest). Another issue with the books is their current availability in some places, but that could be said for any character of a certain vintage.
EVERYONE knows who Deano is.
Of course, with cable and old people around to remind the youngsters, I don't think that they will.
What are you even talking about, none of us are old, nor will we ever be!
The moment I realize I am in the Twilight Zone? Teaching American pop culture to an American...
That was only the sixties. If we are talking "before my time" films, then my love of Elsa Lanchester, Bogey and Charles Laughton might require even more explanation...
The Matt Helm films are great as are the Our Man Flint films. All are great send-ups of the James Bond films, The Man From UNCLE, Secret Agent, and other TV shows from the 50s and 60s. If you haven't seen the Matt Helm or the Flint films you're missing out on a great treat.
For fans of mystery/detective movies I'd recommend The Thin Man series. Great comic send-ups of the great detective movies - and everyone drinks like fish and smoke like chimneys.