The Redemption of Time

This is a Three-Body Problem Paraquel that adds some interesting ideas and reveals a few things to understand a bit more about Yun Tianming and everything that happened during-after Death's End. Here we also confirm how a useless character Cheng Xin is. If you disliked her in Death's End, this book in one page will increase that feeling.
In the other hand, the book leaves the usual SF and Physics approach and plays more with an Ultra Hyper Dimensional Universe of things (some people are considering it Fantasy), and I don't really know how to feel about it.
There is a pretty nice reference to Asimov's Foundation as well.
In a nutshell it's not in the same quality as the original trilogy but it is truly worth a read.

Pd: The English version of this book is coming out in a few months but I'm glad to found out that the Spanish version was already on the bookstores since last year.