The Conspirators: 20th July 1944 (Ballantine's Illustrated History of the Violent Century: Politics in Action No. 1)

As Stauffenberg reached the staff car, the explosion went off with an enormous, deafening sound. Stauffenberg knew at once from its sheer magnitude that his mission must have been successful. It was 12.42 by their watches - the historic moment (he was convinced) of Hitler's death.
The Conspirators: 20th July 1944 is part of Ballantine's Illustrated History of the Violent Century, and is Book #1 in the Politics in Action book series.