Lud-in-the-Mist by Hope Mirrlees
A fantasy tale predating The Lord of the Rings by decades. . . .
Lud-In-the-Mists is the capital of Dorimare, a prosperous country that bordered on Fairyland, and once upon a time had been a duchy before they revolted at the last one's caprice and destructiveness. Now it was ruled by a wealthy merchant class and very content they were, having prohibited any dealings with Fairyland at all -- particularly with its fruit, which has a peculiar effect on those who eat it, who are never content after without it. True, there are plenty of folk beliefs yet, such as the thought that the dead, the Silent People, were taken off to Fairyland to reap the fields of gillyflowers, but in polite society, it was never talked of.
Nathaniel Chanticleer had once, in his childhood, heard a note that haunt him after, but not so much that he did not become a rotund, married merchant, elected Mayor, and having two children. When his son starts to talk of fairies -- in company no less -- he is greatly distressed, and sends for the doctor, Endymion Leer, who scorns the notion that he ate fairy fruit and prescribes a stay at a country farm.
But that does not end it.
The tale involves a finishing school run by Miss Primrose Crabapple, a widow acquitted of murder, a man who changed his name, a book talking about Fairyland's connections with Dorimare, the habit of hanging fennel over doorways, an accidental password, a family crypt and much more, into an enchanting tale. Some may find it slow moving as it builds up the land of Dorimare and all its inhabitants, but I found them intriguing.