In 1611, the seventeen-year-old Gustav Adolf ascended the throne of Sweden. Before the new king could sit on his throne, however, he faced a disastrous war against Denmark, another conflict in Russia, and a rebellious nobility at home. Plus, Sweden itself had an arctic climate and a short growing season. Clearly Gustav II Adolf faced great difficulties even to survive. Yet by the end of the next decade, Gustav II Adolf's Sweden was a leading military...