The Clue of the Hissing Serpent was the 53rd of the 58 books in the Hardy Boys original series. Grosset & Dunlap published it in the familiar blue illustrated cover in 1974 under the Franklin W. Dixon house pseudonym; the novel was written by Andrew E. Svenson for the Stratemeyer Syndicate. It seems a little more formulaic and simplistic than most of the earlier books; Chet has a new hobby (ballooning) that miraculously ties in, the Boys have to fly to an exotic location to wrap-up the action (Hong Kong, which was a mistake because of the casual ethnic racism that's prevalent in the text), Dad is investigating a case that just happens to be linked to what the Boys are investigating, etc., etc. Some of the dialog seems curiously dated: Joe says, "Holy crow!" a lot, and on page 29 he says, "I didn't get all those confounded thorns out of my britches!", which doesn't sound like something a teenager would announce. On page 58 they're up in a ballon and come under attack by men in another balloon and they check on its license plate number... do balloons in 1974 have license plate numbers? The really bizarre thing is on page 150, when the Boys are heading off to Hong Kong to solve the mystery. Their friends throw a surprise going away party and write a song to sing (with a three-piece combo; in 1974?!) to send them on their way:
"Frank, Joe, and Chet, farewell to thee,
Sock 'em, rock 'em
Till the Ruby King is free.
Hello, Hong Kong,
You can't hide Fong
or the slippery Eggleby.
For the Hardys will get you
Sooner or later,
So surrender right now while you can.
They'll give you fits
With their uncanny wits.
They'll always come up with their man!"
Well, that's a thing, isn't it? I'm surprised they came home. There are some clever bits in the plot and a few amusing situations, but overall, I'd say it was more appropriate for a seven-to-eleven-year-old reader than the ten-to-fourteen range advertised on the back cover.