Back in my day Batman was called the "Darknight Detective", which of course has nothing to do with being a knight, but rather referred to the nocturnal nature of the Batman's activities. Knights traditionally serve a liege, so it's a particularly curious term for a vigilante. Was it some curious bit of ignorance that led to the coining of this sobriquet? When did it first appear? Did Miller come up with it?
This is a very interesting question, one I'd really like to hear an answer for. As for my part, I always assumed "Darknight Detective" was a combination of "Dark Knight" and "Detective" - both a crime FIGHTER and a crime SOLVER. It never occured to me that it was "Dark Night Detective." But I guess the absence of a double "K" would suggest that it simply refers to his night-time activity. It wouldn't surprise me if later writers made the same mistake I did - and that "Darknight Detective" was later assumed to be a reference to the "Dark Knight" as a detective, rather than a slightly different, original meaning. Regardless, I cannot remember a particular moment before "Dark Knight Returns" in which he's referred to as the "Dark Knight" (it is perhaps most appropriate in that book, as that's where he rides on horseback - like a knight of old). Of course, he may have been referred to as such in any given single issue - there's no way I'd remember.
I know he's referred to as "the Dark Knight" in an early Bob Kane story, and I think it may even be from the first Joker story in Batman # 1, but I don't have my reference material to hand at the moment, so I can't confirm that.
Darknight/ Dark Knight was always a play on words, referring to both the nocturnal nature of Batman's work and his quest to bring justice. In common parlance a knight has come to mean someone of honor who acts according to a chivalric code. The issue of serving a liege is rarely considered. I believe it is correct that Batman was dubbed Dark Knight in the early days (though that should be credited to Bill Finger, since he was the writer and Bob Kane was the artist). O'Neil added the Detective part in the 70s, and Miller's The Dark Knight Returns revived the original version. Due to its popularity, DC launched the Legends of the Dark Knight title shortly after DKR. Dark Knight has pretty much replaced somewhat sillier sounding nome de plume's such as the Caped Crusader - though it was interesting to hear that one pop up in the latest movie.
Impressive -- you're right! It appears Dark Knight preceded Darknight Detective! Thanks, all, for the responses. I learned something today.
I can. In the last panel of page 7 of the story, the caption reads: "The shock of cold water quickly revives the dark knight!" (It's all-caps, so there's no way of knowing if it was meant to be a title, the Dark Knight, or just a description, the dark knight.) EDIT: Oops, beaker beat me to it, and with pictures, no less. Holy hairsbreadth, Batman!
That comic page is funny, I like how it looks like instead of just illustrating the writer's panel descriptions they added the description to each panel. "A wicked kick rakes the Batman's head" under a drawing of a wicked kick raking the Batman's head. And yet, it still kind of adds something to it.