In this week's Book Club podcast we anticipate the 60th anniversary of the Berlin Wall going up by talking to Iain MacGregor about his book Checkpoint Charlie: The Cold War, The Berlin Wall And The Most Dangerous Place On Earth. Iain takes Sam on a journey though how, and why, the Russians cut a city in half overnight; and why we let them. He describes how events in Tiananmen Square reached Friedrichstrasse. And how, as the Wall came down, a single British soldier did something that the Red Army never forgot.