House of Suns by Alastair Reynolds

An excellent science fiction space opera. Set in the far future, more than 6 million years from now. We follow a human civilisation comprised of Shatterling Lines. Each line a group of clones of the same individual, dedicated to explore and record memories of the galaxy.  Shatterlings travel on their own and meet with the others in their Line every two hundred thousand years or so. Then they share their memories with the rest. They are known as a meta-civilisation as they witness the emergence and disappearance of human civilisations across millenia. This phenomena is called Turn over. No human civilisation (except for a handful) is able to survive more than a few thousand years. The Lines however have survived for 6 million years. The reason perhaps is that they have developed technology to dilate time.

The story starts with a couple of Shatterlings, Purslane and Campion,  on their way to a Line reunion. They are a few years late but that is not a problem. In their last circuit they have met with the Vigilance. An ancient human civilisation,  custodians of a galactic library,  containing data ranging for million of years. Campion is able to meet with a Vigilance and get access to some of their data banks. With that information they set course to their meeting. Still a few light years before arrival they get a distress message from one of their leaders. They had been attacked and annihilated. Years after and ignoring the leader's warning Purslane and Campion arrive at the reunion place finding only devastation. They set on a mission, to find survivors and get revenge. 

Concepts and things I loved:

The vigilance are an interesting concept. They achieved immortality by making their bodies grow perpetually. Now they are the size of spaceship or bigger, their brain takes long to think due to the distances between neurons. 

Hesperus, a robot,  belonging to the Machine People civilisation.  Despite being a Machine he is more human than many other human characters. He stands for friendship and loyalty. 

The Spirit of the Air, a former human being who downloaded his brain, and  now is able to exist without machines. He is admired and feared  by the people in the planet where he lives. Like the Vigilance he has lived for millions of years and has meet with numerous extinct civilisations.

The Priors. Like in other scifi novels I've read, the myths, or ideas about ancient civilisations who existed billions of years before our time. They left the galaxy,  or are extinct,  but their advanced technology is still used by humans.

Not using FTL travel but still be interesting. Fast Spaceships are able to travel just under the speed of light. However still travelling across the galaxy can take hundreds if not thousands of years. Reynolds uses other devices to let his characters survive the pass of time and make the story compelling. There is time dilation due to the fast speeds + stasis technology which allows humans to slow down their perception of time, so they can  travel for hundreds or thousands of years but experience them as a few hours or days.

The immensity of the  novel's scope, in time and space. How the narrative allows for thousands of years to pass and keep the story engaging.

Things I didn't love:

The fantasy like setting in which Abigail, the original human to the Gentian Shatterlings, plays during her childhood. I liked the idea of the game being a mind reading simulation but not the world created by the simulation and the number of pages dedicated to its story. I couldn't understand the connection to the rest of the story.

The Machine People. Their origins and general background was too obscure, being central to the main plot I expected more information about them. Also, for some reason, I couldn't imagine them other way than a 50s robot toy. And here comes another point, I found the concepts and depiction of Artificial Intelligence too simple for  future so far away. Apart from the Machine People (who were just super intelligent and super strong and fast, etc.) The only other AI we see are the spaceship computers something that lacked development and exposure in the novel.