It was a day when the world held its collective breath. This week, 87 years ago, PM Neville Chamberlain had just had his historic first meeting with Adolf Hitler. The question on everyone’s lips was whether it had been a futile last effort to stop an inevitable conflict, or if it really might pull Europe back from the brink of a devastating new war. When it came to the answer, much of it would lie with the attitude of Hitler. Was he prepared to compromise on the details of how he absorbed Czechoslovakia’s Sudetenland into the Reich? Or would he...