Life out of Order by Audrey Niffenegger
Life Out of Order is Audrey Niffenegger's sequel to her much loved The Time Traveller's Wife. Just as in the original book Henry had Chrono-Displacement Disorder, causing him to travel forwards and backwards in time, in the follow-up, his daughter, Alba, and one other character have the same rare Chromosomal abnormality and engage in time travel.
Life Out of Order seems to have divided opinion strongly, with average ratings of 3.44 stars on GoodReads (across 1,675 ratings) and 3.5 stars on Library thing (across 16 ratings), but a good number of high and low readings, with some very negative reviews. I can see why this is, but I love it. I don't think it is quite as good as The Time Traveller's Wife, but it is close, and a highly worthy successor in my view.
Whereas The Time Traveller's Wife is probably best described as a love story set in the context of time travel, and generally a very feel-good book, Life Out of Order is much darker, with climate change and oppression as major themes, though it also has a significant love-story component. In fact, I think the first hundred pages or so are darker (or at least, more unrelenting) than later parts of the book (which has over 500 pages), and that may have contributed to some readers' negativity (particularly, those who report not having finished it). The love story only really emerges later. People also comment on the book being harder to follow, and I suspect that is largely because (in a sense I don't wish to spoil here) there is more time travel, or perhaps a more confusing kind of time travel.
By the end of the book, I felt Niffenegger had captured the same feel and the same universe as the original, and updated it in a way that felt bold and relevant. The book feels very au courrant, not least because it references recent events and projects climate change forward in way that feels all too plausible and realistic to me. Many of the dystopian aspects also strongly reflect current trends and events so that we end up with a science-fiction love story that is also quite contemporary and political.
If you liked The Time Traveller's Wife, I think you would be mad not to try this and persevere for at least 200 pages even if you find the start darker than you would like. Some clearly end up not liking it, but for me it's a worthy and imaginative continuation of the story of Henry, Clare, and the world they inhabit.