I'm going to avoid being spoilery, for the benefit of anyone who wants to read the book and hasn't yet. It's a science fiction story, following the crew of a spaceship called The Wayfarer, in a distant future where several sapient species have spread out across the galaxy, humans being just one of the newer additions, and by far not the most advanced one. The Wayfarer is basically in the business of building wormholes: punching holes in the sublayer between the space so that distant places can be connected and this whole galactic interaction and travel is possible. The book follows the story of the multi-species crew as they journey a long way in space for a particularly big, challenging job.
There's so much I love about this. It's very character-driven, focusing on several fascinating people of varied backgrounds. The characters are all amazing, intriguing and real, and I love how effortlessly diverse this book is. There's same-sex and inter-species romance that mostly isn't a big deal (though there are cultures that don't approve of interspecies romance), there are cultures with very different ideas about family and children and sexuality than human cultures usually have, there are aliens that naturally change sex during their lives or don't have one etc. There are totally kick-ass female characters, in several ways, from the young and smart human clerk to the awesome Aandrisk pilot (the Aandrisks are this totally amazing reptilian-ish species who I want to be adopted by, though they'd find me so weird) to the feisty human engineer who keeps the ship together.
And the male (or currently-male) characters are just as awesome - gender just isn't a factor of how awesme and capable you can be and what your options are. It comes across casually that normally humans are brown-skinned and a white human is very unusual, because mostly the racial characteristics have blended together by now. The current dominance of the Western culture is a thing so much in the past that it's not even mentioned, and there are whole new cultures related to how and when different parts of the species went out to space. Some are very pacifistic due to having learned from traumatic experiences before the rest of the humans left the planet for a better future, while others have left earlier and don't share that history. The other species have incredibly fascinating cultures, from the complex family systems of the Aandrisks (the idea of "feather families" who consist of the friends and lovers you make in your adulthood makes so much sense, and then there are a few other sets of family for various stages in your life) to the unusual spirituality of the Sianat, and I could just go on. Also, I want a Dr. Chef to make me food and check out my health. Though he'd disapprove of my tea-drinking habits, definitely more than three cups a day!
The science part is fascinating and makes sense (the author is the daughter of two space experts, which I'm sure helps), but it's written in such a way that you can understand it without a strong science background.
I also love the happy, hopeful tone of the book. A lot of the time I try to read scifi, it's too bleak and depressing to my liking. This one isn't, yet also doesn't pretend problems away. There's discussion of things having gone absolutely to the shit in the history of the Earth (ie. our future), but also they've survived it, learned from it, and can now try to do better. The tone of the book is full of hope and optimism, despite not being afraid to tackle some very big and serious issues.
Another thing I love is, it looks at a lot of everyday things in such a world, even as they're also embarking on a big adventure. Things like food, games, galactic bureaucracy, effects of gravity on a spaceship, skies on different moons and planets, coping with a multi-species cultural environment, how to speak politely in a society consisting of various species and various forms of gender, sexuality and family. And often problems are solved through means other than who has the biggest guns: for example, Rosemary, the ship's clerk, more than once saves the day by figuring out the right laws and paperwork or by speaking the right language (and trust me, this is done with tension intact!). There's a lot of adventure, a lot of fun, a lot of friendship and strong bonds and big feelings, a lot of touching moments, and so much at stake and so much to win. Oh, I could go on about this book, and I didn't mean to go on for this long, but here we are.
Aaaand it just happens to be on the Yuletide nominated fandoms list, so I'm already tweaking my planned sign-up in my mind. Also, there's a stand-alone sequel coming out this month. I think I'll be making an order.