The Subtle Art of Folding Space by John Chu

Published by Tor Books on April 7, 2026

The Subtle Art of Folding Space may or may not take place in our universe (John Chu acknowledges that this is an open question). It is set on our Earth or one very much like it that exists somewhere in the multiverse. As Chu explains it, the multiverse is like a Russian nesting egg. Each universe has a skunkworks. Each skunkworks generates a new universe, layered over (or beneath?) the universe in which the skunkworks resides. That new universe has a skunkworks that generates another universe, and so on and on and on.

Each universe has its own skunkworks-generated principles of physics. In the novel's universe, quantum mechanics was only installed about a hundred years ago, which is a cute way of explaining why it physicists only recently discovered it.

Ellie is one of many maintainers who are charged with making sure the skunkworks function properly. Three types of maintainer are responsible for the skunkworks. “Architects design the configuration of gates and pipes that generate the next universe in.” Builders install and repair the gates and pipes. Verifiers make sure the architects and builders haven’t made a mistake. Ellie is a builder. She reroutes pipes, patches leaks, does whatever is required to make sure the universe is adhering to the rules that define it.

I grew a bit confused about whether maintainers repair the skunkworks in the universe in which they reside, or whether they repair the skunkworks in the universe that created their own. It seems they sometimes do both, or work in conjunction with maintainers from other universes. That this went over my head is probably more my fault than Chu’s.

Ellie learned her skills from the Chief Builder, her mother Vera. Vera’s brother had a son named Daniel who came to live with her as an infant. Although he is Ellie’s cousin, Ellie thinks of him as a brother. Daniel is a verifier, having also learned his skills from Vera. He tests the integrity of skunkworks modifications by materializing food items and tasting them. The foods he samples all sound delicious.

A rivalry has long existed between Ellie and her sister Chris, manifesting in Chris’ frequent attempts to kill Ellie. Chris explains these attempts as training exercises so that Ellie will be prepared to defend herself from the isolationists that lurk in the skunkworks. More recently, the rivalry extends to care for Vera, who is in poor health. Chris complains that Ellie doesn’t help her care for Vera, but the truth is that Chris prevents Ellie from doing so, perhaps so she can claim credit as the more dutiful daughter.

The plot begins with Ellie’s discovery of a glitch in the physics of her universe. With Daniel’s help, Ellie finds a seemingly new installation in the skunkworks that appears to be keeping her mother alive while, at the same time, making subtle changes in the operation of physics. This creates a moral dilemma. Should she repair the glitch and restore the proper operation of physics — something she believes her mother would want her to do — even if the repair will end her mother’s life?

That dilemma is resolved before the novel’s midway point, perhaps depriving the novel of drama for which the dilemma could have been milked. The rest of the story focuses on the reason the physics-changing installation was added to the skunkworks. Ellie’s attempt to research that question, assisted by Daniel and the Chief Architect, leads her to a new understanding of the isolationists and of Chris’ plan to change everything.

The Subtle Art of Folding Space is a clever, low-key story. Many science fiction novels engage in universe building, but this one shows us the literal process of building a universe. Kudos to Chu for coming up with that high concept.

Ellie and Daniel are engaging characters who may or may not be human — or perhaps they are variants of human from a universe that isn’t quite ours. Daniel and the Chief Architect seem to have powers (some shared by Chris) that make them resemble wizards. Ordinary humans, I assume, can’t transport themselves to the skunkworks.

The plot imagines a clash between selfless maintainers like Ellie who are dedicated to making the universe function for everyone’s benefit and maintainers who are furthering their own agenda, one that might require different principles of physics. While elements of science fiction are thus central to the story, this is fundamentally a novel about a dysfunctional family. Its dramatic tension derives from the clash between Ellie and Chris and Ellie’s belated discovery of the reason Chris has been so mean to her for so long. Ellie has always forgiven Chris because her mother wanted them to have a strong relationship, but Daniel believes Chris to be undeserving of the deference that Ellie accords her.

Science fiction fans who crave stories of humans overcoming alien invasions might not appreciate the smaller story that Chu tells. Science fiction fans who crave detailed explanations of the science that underlies the story may be disappointed by the gaps that Chu leaves. How was the first skunkworks created? Who chooses the maintainers? How do maintainers acquire the power to transport themselves into the skunkworks? How do architects make decisions about the physics that each skunkworks will install in the universe it creates? For sf fans who are content to read an entertaining novel about sibling rivalry in an unorthodox setting, The Subtle Art of Folding Space is a fun departure from the sf norm.

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