The Collapsing Empire is the first novel in a new space opera series by John Scalzi. I don't read a lot of space opera: I've always found disbelief hard to suspend for interstellar settings, especially for serious books. However, John Scalzi is a writer whose books are fun first of all, and then about ideas. They may have serious thoughts, but they do not take themselves seriously. That makes all the difference.
The Collapsing Empire deals with the interstellar elephant in the room in its own way: humanity hasn't discovered technology that makes faster than light travel possible. Rather, it has stumbled upon 'The Flow' - a network of naturally occurring worm holes (by another name) which happens to connect various places in space.
The novel starts with an prologue that very much sets the scene: a mutiny is under way on a space transport ship. The narrative voice is witty, the characters snappy and a bit laid back in the way they speak and face adversity (and death), and suddenly, the mutiny is interrupted when their ship finds itself evicted from the Flow in the middle of empty space, a completely unheard-of calamity...
Meanwhile, in the central Hub of mankind's empire (a giant man-made space habitat which sits at a place where many strands of The Flow happen to meet), the Emperox is about to die, and his only surviving daughter (born out of wedlock) is about to succeed to the Throne, reluctantly. Just before he dies, her father hints that trouble is on the horizon...
The Empire has a Senate and an Emperox and a Church, balancing each other for institutional power, but really, it's a family game, with inherited monopolies on products and industries for each dynasty of robber barons. It's hard not to see some of this setup as a Game-of-Thrones-in-space, but John Scalzi doesn't write his novels to be pompous, serious, or gritty, so the story never feels like a Song-of-Ice-and-Fire ripoff. In terms of tone, think Joss Whedon or Mira Grant, not GRRM.
The story orbits around an ensemble of characters, most of whom are young(ish) people, belonging to that mid-twenties - early-thirties generation, out of uni but not quite fully independent, ready to leave a mark on the world but only very slowly emerging out of the shadows of mom & dad. If the nineteenth century invented kids and the twentieth century invented the teenager, then the twenty-first invented the forever-young-adults, and this book is about people of this generation. People who don't part from their favourite teddy bear, but also have promiscuous sex. People who don't know what they want to be when they grow up, who aren't terribly interested in starting their own families. People who want to live, not just survive, and to do something exciting with their lives, even if they don't yet know what that might be.
It's an immensely readable novel. Fun, tongue in cheek, never boring. At times, it feels a bit like a giant metaphor for politicians' response to climate change, but it's not a deep novel. Space adventures with a group of fun snarky people - who wouldn't enjoy that?