December is a really light month for new science fiction and fantasy books, but there's still some really great stuff out there. Including a new Deryni novel by Katherine Kurtz, a dwarf detective novel, and a Jay Lake collaboration. Here are the most essential books published in December.

Tides of Maritinia by Warren Hammond (Harper Voyager)

We really enjoyed Hammond's KOP novels, and now he's back with a novel about interplanetary intrigue that sounds really fun. Maritinia is a minor little planet on the fringes of the Empire, so they hope nobody will care if they break away and declare independence. But the Empire believes that if one small planet can become independent, then other, more important worlds will follow suit. So they send an operative to the planet to assassinate one of the leaders of the independence movement, foment trouble, and weaken the planet's political leadership enough that the Empire can retake the world with little trouble. With nobody to talk to except the Political Officer, who's basically a second consciousness implanted in his brain, Jakob starts to go nuts and question his mission.

The Maggot People by Henning Koch (Dzanc Books)

In the debut novel by this Swedish writer, a young man falls in love with a woman despite her warnings that he risks turning into a "maggot person." Not a half-human, half-maggot creature, but rather a human whose body is full of maggots that replace your internal organs and perform the same functions as your heart, lungs and other parts. And it turns out there are others. Kirkus praises the philosophical musings in spite of too many far-fetched plot twists, and says "fans of creepy sci-fi–tinged thrillers will enjoy this book."

The King's Deryni (A Novel of the Deryni) by Katherine Kurtz (Ace)

The conclusion to the Childe Morgan trilogy, and the first new Deryni novel in ages and ages. Brion has finally turned 18 and ascended to the throne, and his friend Alaric Morgan is called to court because the two boys share a mystical bond. But Alaric has to struggle with the prejudice that many people have against the Deryni, and meanwhile Brion is making some rash moves to expand his power. Read an excerpt here. RT Book Reviews calls it "a fantastical blend of magic and passion written with a keen eye for detail."

Elysium by Jennifer Marie Brissett (Aqueduct)

This debut novel is winning raves from people like Jeffrey Ford, James Patrick Kelly, and Publishers Weekly, which liked its deft handling of questions of identity. The main character is either Adrianne or Adrian, depending on which reality we find her/him in, and he/she keeps meeting a lover who's either Antoine or Antoinette. And it turns out there's a computer code etched into the atmosphere of Elysium, which contains the story of these two people and is breaking down because it's been corrupted.

Macaque Attack! (Ack-Ack Macaque) by Gareth L. Powell (Solaris)

The first Ack-Ack Macaque novel won the British Science Fiction Award, and now Powell is concluding the trilogy with a story in which the universe-hopping monkeys fight against killer androids. And the Ack-Ack Macaque prepares for the biggest challenge of all: fatherhood. Read an excerpt here.

Detective Strongoak and the Case of the Dead Elf by Terry Newman (Harper Voyager)

It's a detective novel set in a world of gnomes on drugs, goblins with guns and mysterious elf corpses. Nicely Strongoak is a dwarf detective who does his best to unravel the secrets of a city full of corruption, but after he's framed for the murder of an elf, he'll need all his wits to uncover the truth.

Undercity (Skolian Empire) by Catherine Asaro (Baen)

First book in a brand new series — Major Bhajaan has quit the Imperial Space Command, and now she has to adjust to civilian life. By becoming a private detective, in the mean streets of the Undercity. She's sent to track down the son of a nobleman who's either run away or been kidnapped, and in the process we learn a lot more about the gritty underbelly of Asaro's Skolian Empire.

The Collected Stories of Carol Emshwiller: Vol. 2 by Carol Emshwiller (NonStop Press)

This second volume of Emshwiller's collected stories includes 56 tales that weren't in volume one, including a lot of her most acclaimed tales. We actually included this book in our listing of last December's must-read books, but apparently it was delayed for a whole year.

Our Lady of the Islands by Shannon Page and Jay Lake (Per Aspera)

Page and Lake were collaborating on this book, set in the same world as Lake's novel Green, for a few years before Lake passed away. Now Page has completed their collaboration on her own. It's the story of Sian Katte, a businesswoman in the tropical land of Alizar, who gets assaulted, and gains an unwanted magical power. And Arian des Chances, the wife of Alizar's ruler, who's watching her son die. This was chosen as one of the best SF books of 2014 by Publishers Weekly, which praised its "emotionally authentic, coherent voice."

Sources: SFSignal, Locus, Amazon and Publisher Catalogs