As the war in Europe entered its final months, we teetered on the edge of a Third World War. While Soviet forces smashed their way into Berlin, Churchill ordered British military planners to prepare the top secret Operation Unthinkable - the plan for an Allied attack on the Soviet Union, on 1 July 1945. Using US, British and Polish forces, the invasion would reclaim Eastern Europe. The plan called for the use of the atomic bomb and Nazi troops if necessary, more than merely controversial, as the extent of the Holocaust was becoming clear. Would yet another army make the fatal mistake of heading East? In Operation Unthinkable Jonathan Walker presents a haunting study of the war that so nearly was. He outlines the motivations behind Churchill's plan, the logistics of launching a vast assault against an enemy who had bested Hitler, potential sabotage by Polish communists, and whether the Allies would have succeeded. Well supported by a wide range of primary sources from the Polish Underground Museum Study Trust, Sikorski Institute, National Archives and Imperial War Museum, this is a fascinating insight into the upheaval as the Second World War drew to a close and the Allies' mistrust of the Soviet Union that would blossom into the Cold War.

JONATHAN WALKER is a member of the British Commission for Military History and a former Honorary Research Associate at the University of Birmingham. He is the author of five books for Spellmount: The Blood Tub: General Gough and the Battle of Bullecourt; War Letters to a Wife (as editor); Aden Insurgency: The Savage War in South Arabia; Poland Alone: Britain, SOE and the Collapse of the Polish Resistance, 1944 (which has been translated into Polish to great acclaim); and The Blue Beast: Power and Passion in the Great War. In addition to contributing to other recent military history publications, he has appeared on BBC radio and television programmes. He lives
in Devon.