The Children of Possibility

On second reading, I enjoyed this more than I expected to, and I'd like to give it 3½ stars; but I still have mixed feelings about it, and I think 4 stars would be going too far.

On the plus side, it makes a good story, and it's an original take on the subject of time travel: it's unlike any other time-travel stories that I've read. The author is an experienced writer who seems to know his way around various different sciences (which is handy when writing science fiction).

On the minus side, although characterization is adequate, the characters don't have much personality. I like to enjoy the company of fictional characters, but I don't get much out of these.

Although the story is clearly science fiction, the characteristics of the Möglichen (an elusive class of sentient beings) are so bizarre that they seem creatures of fantasy; and I don't usually approve of mixing sf with fantasy.

The story has a beginning and an end, and can be read as a standalone novel. However, if you want more, the author later wrote both a sequel and a prequel.