I'll nominate Nation by Terry Pratchett
Spoiler:
Starred Review. Pratchett again shows his humor and humanity. Worlds are destroyed and cultures collide when a tsunami hits islands in a vast ocean much like the Pacific. Mau, a boy on his way back home from his initiation period and ready for the ritual that will make him a man, is the only one of his people, the Nation, to survive. Ermintrude, a girl from somewhere like Britain in a time like the 19th century, is on her way to meet her father, the governor of the Mothering Sunday islands. She is the sole survivor of her ship (or so she thinks), which is wrecked on Mau's island. She reinvents herself as Daphne, and uses her wits and practical sense to help the straggling refugees from nearby islands who start arriving. When raiders land on the island, they are led by a mutineer from the wrecked ship, and Mau must use all of his ingenuity to outsmart him. Then, just as readers are settling in to thinking that all will be well in the new world that Daphne and Mau are helping to build, Pratchett turns the story on its head. The main characters are engaging and interesting, and are the perfect medium for the author's sly humor. Daphne is a close literary cousin of Tiffany Aching in her common sense and keen intelligence wedded to courage. A rich and thought-provoking read.
Critics praised Nation as a hybrid, deeply philosophical book aimed at young adults, but one likely to appeal to adults as well, much like Philip Pullman’s His Dark Materials trilogy or J. K. Rowling’s Harry Potter series. With echoes of William Defoe and William Golding, Nation takes the form of a “classic Robinsonade,” notes the Washington Post—that is, a book in which characters on a desert island recreate civilization. As his characters grapple with questions of leadership, humanity, and survival, Pratchett explores fundamental ideas about religion and culture. This might all sound rather heavy, but there is plenty of originality and humor—and cannibals, spirits, and secret treasures—to go around. In the end, Pratchett offers a vision of a deeply humane world. “In some part of the multiverse there is probably a civilisation based on the thinking of Terry Pratchett,” writes the Guardian, “and what a civilised civilisation that will be.”