In 1992, David Crystal and his editorial team are busy preparing a new edition of The Cambridge Encylopedia for press, when he receives an unexpected visitor. Within days he finds himself deep within a world of international counter-espionage in which the encyclopedia turns out to play a central role, and his life is in serious danger. Embargoed for 25 years, the story can now be told of what might have happened during the volatile months of the break-up of the Soviet Union. Some of the events are true.