TL;DR: A tale of post-humanism, so post-human that it's rather hard to follow.
TL: I've read books with pretty epic timescales, but nothing comes close to the scope of the novellas that make up Sister Alice. Assuming that everything I read was interpreted correctly, this story does attempt to cover the (currently) expected lifespan of our universe. The only other book that I recall attempting this is The Three Body Problem, difference being that what ends up representing humanity at the end of Sister Alice is very much not something we would really recognise as human. Definitely in the physical realm anyway, I'm debating the actions and behaviours of the characters but, on reflection, the usual tawdry human emotions do drive the actions of the entities involved.
Sister Alice is the first novella, and sets the scene for the rest of the book. Even the scene setting is gargantuan in scope: humanity has reached the stars, and taken to squabbling there just as we do over our limited geography currently. However that's just the prologue, humanity has realised the foolishness, not to mention the existential threat, of continuing down this path and so came up with the concept of The Families. 1000 individuals were chosen from across the (human) population of the known human expansion and each of those individuals was given a mandate: become the head of a genetically distinct "family" by promulgating your exceptional (as tested) characteristics and genetic "goodness" magic by only having children through cloning and then make good decisions on behalf of humanity (it feels like a bit of a colonial setup actually). We don't get any real insight into that process because the story actually starts 10 MILLION years after the Families are set up! Million. The prologue for the story is already epic in scale.
We meet our protagonists, Xo (Nuyen), Ravleen (Sanchex) and Ord (Chamberlain) as children, learning War by running a snow-fort based battle. However what had appeared to be tween/teen-aged characters are quickly revealed to be 50 year-olds, and these characters appear to have a pretty ephemeral attachment to their corporeal forms. This is all covered at high-speed, actually it's not covered at all, I think my explanation is analogous to what the book explains, and therein lies my biggest problem with the book as a whole. Clarke's adage that "Any sufficiently advanced technology is indistinguishable from magic" must inevitably come into play on timescales of this nature, and so, I guess, Mr Reed elected to pare down the story to what he wanted to tell and just elide explanatory dialogue as superfluous to the plot. Whilst this may be true, I think that what it left behind was a series of events happening around, to and through our protagonists, but with little in the way of framework on which to hang an understanding of the story as a whole.
The second novella, Brother Perfect, is easily the most accessible, containing perhaps the one and only character who's ever really given time to explain themselves. This was the part I enjoyed the most and was really the last chunk of the book that attempted any kind of mollycoddling of the reader by attempting to wrap concepts in trappings of humanity, things get progressively more and more abstract from here.
I rated this two-stars because it's neither a story, nor a technical exposition, but something lost in between. To claim that I "liked" it might be a stretch, but I certainly don't regret reading it at all; I almost feel like this is something aspiring science-fiction writers to-be should read! It's constituted of the raw concepts from which many stories could be fashioned, and I think it's doing the job that I expect science fiction to do, of, if not communicating, at very least exposing readers to concepts rarely encountered in day to day life.