From Murder at the New York World's Fair, by Freeman Dana:

[This mystery--by Phoebe Atwood Taylor, aka Alice Tilton, writing under yet another name--has the distinction of being sealed into a time capsule with other 1939 World's Fair materials.]

***

[From the introduction to the 1987 reprint edition, by Dilys Winn. I gather that the book had long been out of print when it was reissued.]

Surely, under whichever pseudonym, Mrs. Taylor is the mystery equivalent to Buster Keaton.  And never more so than here, where she surrounds her patrician Boston grande dame with fan dancers, licentious potentates... officious dignitaries, demented relatives, spurious artwork, window-shades in private train compartments, tour guide disguises, marching bands, traveling salesmen, a suitcase stuffed with a snake, fairground jitneys, fairground VIP limos, private eyes tailing the wrong people, wallpaper samples, and a newspaperman sidekick who hero worships our heroine's nephew.

***

[More from Winn's introduction.]

I am truly addicted to the 8 titles that appeared under the nom de nonsense Alice Tilton. Closer in feeling to World's Fair [than Atwood's other main series], these books don't make all that much sense, but they go a long way in proving that making sense is immaterial....

***

What she had just seen in the corridor had bewildered her to a point of forgetting everything, even her far-seeing glasses.

***

"To be any good," Sam explained, "a fair has to have a theme. This fair's got two themes, so it'll be twice as good."

***

"Isn't that the building that has that--oh, you know. That thing. You know what I mean!"

She was, she felt, on perfectly safe ground. Every building at the Fair was sure to have something as a feature attraction.

***

"After yesterday," Sam went on, "I could pick Glue's face out of a million. Why, I dreamed about his eyebrows last night!"

***

She would have preferred almost anyone... to Elfrida in a militant mood. And Elfrida was militant. Daisy knew that by the way the feathers bobbed back and forth on that awful blue hat.

***

"Oh, you do, do you?" the plainclothesman said. "You do, huh?"

His irony sailed over the feathers on the blue hat.

***

[Literally Giving Someone a Penny for Her Thoughts dept. (Did people really do that?)]

Sam pressed a penny into Daisy's hand.

"I wasn't thinking much," Daisy said.

***

[From a letter Taylor wrote to the book's original publisher, Bennet Cerf, as reproduced in the reprint edition's afterword. As part of her extensive research, Taylor had visited the fair site while it was still under construction.]

"You've no idea how many [novel-plotting] obstacles an incomplete Fair can make."

[From the same letter.]

"After all, the bare outline of a mystery plot is simply, X gets killed; dither; Y gets killed: less dither. [Note the introduction of a colon after two semicolons.] A catches B."