Shortlisted for the Arthur C. Clarke Award 1987

"conceptually Eon knocks Rama out of the park ... a classic of breathless exploration" - Stephen Baxter

"There should be a picture of Eon in the dictionary: right next to 'Sense-of-wonder-SF'" - Goodreads Reviewer, 5 stars

"When I look for SF, it's BECAUSE of this book" - Goodreads Reviewer, 5 stars

Above our planet hangs a hollow Stone, it came from out of nothingness and into Earth's orbit. Within it there are a vast number of chambers to explore, containing forests, lakes, and rivers. Some chambers even contain deserted cities, and the remains of a lost civilisation. Scientists determined that the Stone was from space... but perhaps not our space; that it came from the future... but perhaps not our future.

While scientists and politicians bicker about how to use their newfound discoveries, the Stone harbours a secret that makes even Earth's survival pale into insignificance.