The Nazi siege of Leningrad from 1941 to 1943, during which time the city was cut off from the rest of the world, was one of the most gruesome episodes of World War II. In scale, the tragedy of Leningrad dwarfs even the Warsaw ghetto or Hiroshima. Nearly three million people endured it; just under half of them died, starving or freezing to death, most in the six months from October 1941 to April 1942 when the temperature often stayed at 30 degrees...