Hitler's lightning invasion of Poland in 1939 was the real beginning of World War II in Europe. This was the period when armored warfare inscribed itself into global consciousness as the Poles desperately sought to stave off the Blitzkrieg. At the heart of the fighting on the ground, large numbers of Nazi Germany's PzKpfw II battled against Poland's better-armed but much less numerous 7TP tank. The two types both possessed unique strengths and...