The Long Utopia

While The Long Utopia continues the overarching narrative of humanity's expansion across parallel worlds, it can be enjoyed as a standalone adventure. The authors provide enough context for new readers to understand the premise and character motivations without having read the earlier installments.

The Long Utopia, co-authored with Stephen Baxter, features a more traditional science fiction narrative with a focus on exploration and grand concepts, differing from the satirical fantasy and philosophical humor often found in Pratchett's Discworld novels. While Pratchett's wit is present, it is integrated into a distinct hard science fiction framework.

Many readers find it slightly more sober — both characters and the world have aged, and the threat in this book is larger and stranger than the political conflicts of the earlier volumes.

Yes. The Long Utopia is book four in a continuous series.

By the time The Long Utopia was written (published 2015), Pratchett's posterior cortical atrophy had advanced significantly. Stephen Baxter has noted that the collaboration became more one-sided in the later books, with Baxter doing more of the drafting work.