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