"Proof of Concept is proof that Gwyneth Jones is an international treasure. If she writes it, you need to read it––that's all you need to know." —Pat Cadigan, Hugo and Clarke Award-winning author of Synners.

"Proof of Concept by Gwyneth Jones is deeply unsettling and utterly transcendent.” —Kathleen Ann Goonan, Campbell Award-winning author of the Nanotech trilogy

“Proof of Concept engages and excites, its puzzles unwrapping with deft speed. I liked it a lot. Prepare for concept acceleration!” —Gregory Benford, Nebula Award-winning author of Timescape and the Galactic Centre series.

“Proof of Concept has almost everything: a truly fascinating setting in a deeper cave than any we have yet found, an interesting near future society, virtual sex, an AI, a likeable young heroine, a planet (Earth) that's in dire trouble and Post Standard Model Physics that may (or may not) solve the planet's problems. A dense, unsettling, compelling tale written in Gwyneth Jones' usual fine style. I want to visit the cave, and I wouldn't mind knowing more about the theoretical physics.” —Eleanor Arnason

"A terrific, intricately wrought matryoshka doll of a story, crammed with weird science, steeped in the ambience of an authentically strange but thoroughly plausible future." —Paul McAuley

"A delicious portrayal of what it feels like when that nagging voice in your head telling you something is wrong is in fact your only ally." —The Washington Post