From the bestselling author of Headlong and Spies, and "an unconditional triumph and " (The Washington Post Book World)For fifteen years, ever since the taciturn civil servant Summerchild fell to his death from a window in the Admiralty, there have been rumors.So Brian Jessel, a young member of the Cabinet Office, is diverted from his routine work and asked to prepare an internal report. Slowly, from the archives in the Cabinet Office Registry, Jessel begins to reconstruct Summerchild's last months. It begins to emerge that, at a time when America had just put men on the moon, the British were involved in an even bolder project, and that Summerchild was investigating a phenomenon as common as sunlight, but as powerful and dangerous as any of the forces that modern science has known.The secret world into which Brian Jessel stumbles turns out to be even more extraordinary than his department had feared.