Decoding the Heavens
The 'Antikythera Mechanism' as it became known turned out to contain gear mechanisms which shouldn't have been possible until over a thousand years later. Although writings from Ancient Greece had hinted at the possibility of such devices, it had seemed unlikely that they had actually been made. This object changed that view. But as it was so corroded, any attempt to work out what it was for seemed to be mostly guesswork. As technology has improved though, in particular X-ray technology, it has been possible to study it in more detail, and within the last decade a convincing explanation of its purpose had been found.
Its the sort of puzzle that researchers can become fixated upon solving. With restricted access to the object and different groups working on the solution, this has lead to a fair amount of competition and disappointment. The book tells a fascinating story of an important object in the history of technology - one that I hadn't heard of before - and I would recommend it as well worth reading.