What If?: The World's Foremost Military Historians Imagine What Might Have Been contains "How Hitler Could Have Won the War" by John Keegan. Virtual History: Alternatives and Counterfactuals, edited by Niall Ferguson, contains "Hitler's England: What if Germany had invaded Britain in May 1940?" by Andrew Roberts and Niall Ferguson, plus "Nazi Europe: What if Nazi Germany had defeated the Soviet Union?" by Michael Burleigh.