I thoroughly enjoyed this book. With such a cryptic title I wasn't sure what to expect, and even now I can only symbolically interpret the title with respect to the story. A Fire Upon the Deep won (in a tie with Connie Willis's Doomsday Book) the 1993 Hugo award, which is arguably the highest award for a sci-fi/fantasy book. And I have to say it is richly deserved. The world, or perhaps I should say universe, is so richly detailed that I wish I could spend more time reading it (and there are other books set in it, including a direct sequel; hooray!). The plot draws from simple ideas, but expands in very cool ways and keeps you deep in the story. And the characters are cool too: even the alien ones have feelings and thoughts we can relate to. There are so many different ideas and concepts in the book that it almost feels overwhelming, yet Vinge is able to gather everything together and deliver an amazing, imaginative narrative.
The story itself deals with what happens when human scientists accidentally release a sinister agent that begins attacking civilizations around it. However, the key to unraveling the mystery lies in a ship that crash-landed on a distant world with medieval-level society. A race to be the first to reach that world ensues amidst the Galactic-scale turmoil of the unleashed Blight. That planet in question, however, is at the verge of war as two opposing sides struggle to control the advanced technology from the ship that has fallen onto their world.
Here's a video with a quick introduction to (part of) what the book is about:
There are three main parts of the story, though the connection between them is very clear from the start. The first is the large-scale Galactic conflict of the spreading Blight. This is told in a clever manner via short messages sent along the Galactic Net. Think of it like accessing a forum, or a Galaxy-wide Facebook. Through it, we get to see far distant species as they struggle, and fall, under the onslaught of the Blight. Thanks to the Net and ultralight travel, we feel the threat of the Blight, and it's repercussions, throughout the whole story.
The second part of the tale is the story of a human librarian, Ravna. She interprets a lot of the Net messages regarding the Blight and we get to see the more personal struggle between those affected, especially given that humans are not exactly favorably viewed given what they did. She is the link between the first and third parts of this story. Ravna, along with Pham and two Skroderiders, goes on a mission to find out if (and how) they can save the Galaxy.
The last part of the story occurs in Tines World. Survivors from the lab that unleashed the Blight have crashed there and find themselves in a hostile, medieval world. The residents of the planet are smart enough to realize the importance of the advanced technology they see and start working to figure out how to improve their weapons against each other. Their struggle is close and personal, but puny in the face of the Galactic conflict beyond their system.
There are many characters and various races we meet in the story. These are described in enough detail that we can image them and the author even risks placing some of them as the viewpoint characters. This can be tricky in science fiction stories as you can have a non-human be so confusing as to be completely un-relatable or have one that is so human it feels fake. Vinge is able to balance this perfectly and instead offers a great view into these diverse characters.
Among the humans we have Ravna, Pham, Jefri, and Johanna. Pham is a bit of an enigma, and his story and relationship with Ravna is something I won't spoil. Jefri and Johanna are both children but are stranded among the Tines. While Jefri is open and friendly, Johanna lashes out with violence. The interplay between the two children and the Tines is probably one of the more interesting aspects of the book character-wise.
The Tines are my favorite race in the book, particularly given that we spend so much time with them. They are somewhat like a blend between a rat, dog, and seal. Imagine a smallish dog with a long smooth neck and you have a good idea what a singleton looks like. The neat thing is that a 'person' among the Tines is comprised of at least 4 and usually up to 6 of such creatures: a pack.
We see many different packs, but the most prominent ones are Peregrine, Amdi, Woodcarver, and Lord Steel. These are 'taken' names which is what the pack adopts as a whole. They can also refer to themselves by the pack name: Peregrine is Wickwrackrum, a pack made of Wic, Kwk, Rac, and Rum. Despite their alienness they end up being very relatable and amazingly engaging.
We also see a few Skroderiders, of which Blueshell and Greenstalk are the main ones. Imagine a small tree and place it on a pot. But have the pot be instead a cart, so the tree can move around. And have the tree be intelligent and capable of speaking. That gives you an idea of how odd the Skroderiders (sometimes called Skroders or Riders) are.
Setting / World Building
We get to see some pretty neat locations across the Galaxy. For example, at Relay, many people live in a large structure (the Docks) held up by antigravity devices. Being so high up above the atmosphere they get excellent views of the night sky and, since the planet is so far above the Galactic plane, they witness a galaxy-rise nearly every night. It reminded me of Carl Sagan's quote: "A still more glorious dawn awaits / Not a sunrise, but a galaxy rise / A morning filled with 400 billion suns / The rising of the milky way" and the associated music video.
In Tines World, we see the packs and they are a cool hive-mind-like species. Their minds communicate with each other via sounds and so a pack cannot extend itself too much or come into close contact with others. That leads to some very interesting situations. For example: if a single member dies the 'person' lives on and can add another member to replace it. A new member, however, is different and so the soul and personality of the original pack will change. There are many, interesting implications of the pack-minds and what you can do with them. The author explores the coolest ones, but I'm sure that as a reader you can come up with some interesting scenarios.
Also interesting is the nature of species that go beyond the Beyond. How the species change and how long they survive in the Transcend is left somewhat of a mystery. However, there are plenty of clues as to their nature (they are commonly called Powers) so a reader can piece together an idea of what they are. The Blight is also an interesting entity, but I won't comment on that here, since a fun part of the book is the struggle to figure it out.
This is clearly one of the better science fiction books I have read recently. There are so many diverse concepts --- Galactic struggles, Zones of thought, group minds --- that each one alone would make for a great story. Vernor Vinge has managed to tie all these varied ideas, along with some cool characters and a good plot, to tell an amazing epic story in the grandest of all scales. I highly recommend this book and will very likely be reading additional stories set in the Zones of Thought universe.