An interesting intergalactic adventure with a philosophical bend. The Solar system is suddenly transported to a new cluster of stars and humans find themselves in the middle of alien politics and conquests.
There are a couple of things that really stand out for me:
The philosophical layer of the book delves into the nature of reality, spiritualism, souls, thoughts, and the interaction between them, yet attempting to formulate these from the perspective of quantum physics. It is very beautifully accentuated by the poems by a strange character named Mad Erik, which appear at the beginning of every chapter (quite possibly my favourite character in the book).
The medley of alien races are wonderfully whimsical: invented and described with an almost child-like delight that reminded me at times of Douglas Adams's writings and at time felt like Alice in Wonderland stepping into an alien candy store.
There is also a more serious story line that deals with the attempts to bring the human race onto the same page in order to counter the looming threat. Diplomacy, negotiation, technological development all play a part, as they would in real life.
One thing that I would have liked would be a little bit more scene-setting at the start. For example, it took me a while to work out that the appearance of the star Cluster was an unexpected event and not part of normal existence within the novel's world. Transitions to storylines of different alien species were at times confusing. Exposition is a tricky one to balance and authors are often told to avoid it, but a bit more explanation as part of the world-building would have made the story lines clearer, I think. (In my case, it might have also been a bit confusing because I was reading the novel on my phone, in small bursts over a couple of months.)
I loved the characters and the philosophical discourses.