Researching the war between Britain and Nazi Germany, which lasted from May 1940 to May 1941, historian Stuart Gratton becomes intrigued by the enigma of J.L. Sawyer, an obscure figure who played a key part in bringing the conflict to its conclusion. As he digs deeper, he discovers there were two J.L. Sawyers - identical twins Jack and Joe, one a fighter pilot and the other a conscientous objector - divided both by their love for the same woman and their attitudes towards the war. But as the brothers' story emerges from books, letters, and diaries, the evidence does not all add up, and there may be an even wider separation between them - divergent realities, in which different possibilities and unexpected truths emerge, and nothing is quite what it seems. Both a brilliant historical novel about World War II and one of the best works of alternate history ever written, Christopher Priest's earned the Arthur C. Clarke and BSFA Awards and ranks among his finest achievements. Like his classics and , it is an engrossing literary puzzle that will keep readers turning the pages until its startling conclusion. 'An astonishing achievement.' - 'A masterly novel that deserves to become a classic.' - 'A complex and enigmatic tale of identity, illusion and deception.' - 'Superbly constructed, the prose admirably spare and elegant ... a queasily gripping and intelligent work of fiction.' - 'A subtle, unsettling alternative WWII history.' - (starred review)