I've never read anything by Georgette Heyer, and know next to nothing about her (only that she seems popular enough to have novels published with some frequency, and to focus on historical novels). And stories in which people dress like these guys and hang out in places like that don't really interest me all that much. Hell, prose fiction in general doesn't generally interest me all that much.
Nevertheless, when I saw that cover on a copy of the book at the library, I was sorely tempted to bring the book home and start reading, just so I could learn what the hell was going on in that cover image, with the guy on the left reacting to the gentleman walking down the stairs as if the second man had been sprayed by seventy skunks. Or maybe the first man had taken a ton of acid and was having some crazy bad trip, and is hallucinating that the second man was made of writhing cockroaches or...Well, I can't imagine why that dude is reacting to the other dude like that, which is why I was tempted to pick it up, take it home and read it.
That used to be the whole idea of comic book covers, didn't it, before the days where characters posing or otherwise trying to be presented as iconic became the norm...?