The historiography of the Thirty Years’ War has not traditionally focused on the period after Albrecht von Wallenstein's death. Perhaps this is because the major figures of the last part of this conflict are less congenial subjects than Gustavus Adolphus or Tilly—or less compelling antiheroes than Wallenstein. Studies of the period following 1634 have been dominated by a turn to France. This book aims to fill these gaps. It is written in great detail and is the product of years of prodigious research. Wallenstein stands behind it like a specter.

The decade from 1635 to 1645 began with a high point for the Imperial forces but ended with failure. Ferdinand III regarded France as his main enemy, and in 1636 he did not yet think about bringing the war with Sweden to a quick end. Instead, he allowed the Saxon army to take care of the Swedes in the eastern part of Central Europe, which failed. The turning point of the war, as Höbelt argues, was the campaign that followed. In 1637 the Imperialist general Matthias Gallas led a large task force into Pomerania. They succeeded in pushing the Swedish army back up to a fringe of fortresses along the coast, which could be supplied by sea—but only just. The garrisons inside may have been starving and ragged, but they were there, and the Imperialists never managed to take all these forts. Gallas's army could not feed itself in Pomerania and the Mark Brandenburg, which was fatal, for since the Peace of Prague, the power of the Imperial Estates had grown. Gallas was not willing to alienate them by quartering troops on them, like Wallenstein probably would have been, while the emperor did not allow him to winter over in the Hereditary Lands of the House of Austria. The campaign lasted for three years: no Imperial army had ever stayed so long in the field. Gallas was forced back onto the south bank of the Elbe, and his army collapsed in the winter of 1638–39. A similar opportunity to end the war quickly did not arrive again.

In contrast to Gallas's reputation as a bungler, Höbelt reveals that Gallas knew that without decent winter quarters and local supplies his great armada would collapse. He left no doubt that it was impossible to supply his army on money and convoys from friendly territories alone. The tragedy of the Herrverderber lay not in incompetence, but “in the obedience that that never let him make his professional judgement against the political will of his lord” (214). Wallenstein's downfall began when he was unwilling to impose winter quartering on Bohemia, but Gallas was loyal—to the end of his career and reputation. He paid in 1638 for what he had done in 1634.

This book is part of a trend in recent scholarship, my work included, that attempts to take seventeenth-century warfare on its own terms. Höbelt is conscious of the difference between warfare in this period and the “classical principles” of military analysis, which in fact describe war in the eighteenth or nineteenth century. For instance, armies spread out, against the principle of “concentration of forces”; only the possession and control of territory could secure the retention of troops (25) because soldiers supplied themselves from the land they dominated. Armies were already small in the last half of the 1630s, and they got tinier in the 1940s, with a high proportion of cavalry. The author does a masterful job of contextualizing the extreme mobility of these little forces: their movement was neither uncontrolled nor random. Colonels were in frequent communication with “home base,” and Vienna reacted quickly and flexibly to circumstances in the field.

Both the Swedish and the Imperial armies struggled during the last ten years of the Thirty Years’ War, but the Imperialists were hamstrung for several reasons. It was more difficult for their soldiers to supply themselves directly off the land because the rights of the Estates had to be respected. Moreover, by the 1640s, Swedish garrisons were studded across the eastern part of the Holy Roman Empire. The Imperialists had to maintain control over the areas they wanted to win over by quashing these garrisons, while all the garrisons had to do was survive. Meanwhile, the emperor refused to allow troops to be quartered inside the Hereditary Lands. While the top Swedish generals were free to act based on logistical imperatives and deal with the political consequences later, the Imperialists had to follow political imperatives and suffer the logistical consequences. Their armies remained undernourished and irregularly paid. Höbelt's verdict on Gallas's Pomeranian campaign is a verdict on the entire Imperialist war effort after the Peace of Prague: “It was not that a logistical collapse led to the loss of political control, which is [commonly] argued, but that the attempt to impose political control despite the frictions of war led to a logistical collapse” (446).

Making war in the early seventeenth century was more difficult than many historians fully grasp. One of the strengths of this book is that Höbelt is aware of this. It was especially difficult to coordinate the action of several allies at once. The Spanish Habsburgs and the Imperial Habsburgs struggled to work together: the author argues that this lack of coordination between the two branches of the dynasty and the weakness of the Habsburg position at the end of the Thirty Years’ War were preconditions for French dominance in the era of Louis XIV (233, 436).

The author concludes that the empire lost the Thirty Years’ War, but he does not say that Sweden won, or what winning would mean. If it means to make gains and consolidate them, and save them for one's descendants, then Sweden did not win either. Perhaps the structural characteristics of early modern war mean that lasting victory was possible for very few polities. For all others, their lofty goals seep away like water into sand (410). As Höbelt points out at the very end, the Swedish army never seemed to ask itself what it intended to do in Germany to begin with. Their empire, like many early modern military gains, was ephemeral. Even Louis XIV, who was born the year Banér laid some of the groundwork for his eventual domination of Europe, was eventually fought to a standstill by coordinated efforts led by the House of Austria.