The men who advised and sometimes fought for the Habsburgs were often more remarkable than the rulers they served. Well-born in Bohemia, Albrecht von Wallenstein was not well-to-do. Nevertheless, rising from an adolescent chamberlain to Emperor Matthias to generalissimo of Emperor Ferdinand II's armies in 1625, he also became one of Central Europe's richest landowners. Marriages to propertied heiresses helped; so did possession of the extensive Baltic duchy of Friedland that Ferdinand conferred upon him.

Mortimer's description of Wallenstein and Ferdinand's bond is right on the mark. The Habsburgs needed high officers with the fiscal imagination and versatile military skills that made Wallenstein famous. For his part, only Ferdinand and those who succeeded him as emperors could legitimize and defend Wallenstein's new territorial acquisitions and titles. The author is equally good at clarifying the labyrinth of private ambitions and external circumstances that eventually drove sovereign and general apart. Wallenstein had a knack for making important enemies, military and civilian. Not all of Ferdinand's courtiers wanted newly-rich upstarts in their midst. Several German princes did not like him either; they suspected that he wanted the imperial crown for himself. Wallenstein's increasingly idiosyncratic responses to orders from Vienna, along with his indifference to Catholic political and confessional priorities, exposed him to repeated criticism from dangerous sources. Ferdinand eventually accepted arguments for removing Wallenstein from further command, even for killing him, if the latter's loyalties to the house of Habsburg were as dubious as the emperor's advisors and confidants said. The morbidly ill former general was assassinated in a carefully thought out plot in 1634.

Such gross simplifications of the Wallenstein saga do not prepare readers for the intricacies of Mortimer's research and analysis. Nor do they address the revisionist mission Mortimer has assigned himself in this book. But the audience for the book should know that a conventionally linear narrative lies beneath the welter of military maneuvers and backroom intrigues packed into the study. The author seems to have thought that his work required explanatory charting. Each chapter starts with a title and a parenthetical subtitle; the latter in the form of author's names (Conan Doyle, Dickens, Moliere) or literary works (Othello, Twelfth Night). While not out of keeping with the “Enigma” of Mortimer's title—Edward Elgar kept his audiences guessing about the subjects in his “Enigma Variations”—historians are more likely to be baffled, even annoyed, by the game.

The author's goal was to provide an account of Wallenstein, free of the bias and legend he found in earlier studies, including Golo Mann's elephantine Wallenstein from 1971. Given his purpose, Mortimer's research strategy seems somewhat perverse. Even as he criticizes earlier work, he relies heavily on the vast body of primary and secondary material on Wallenstein and the Thirty Years' War that appeared in prior centuries. His illuminating exploration of Wallenstein's relatively modest role in the complex currency scandals of the 1620s draws much from Chapter 4 of Mann's Wallenstein, which is one of his critical targets.

Revisionist history usually builds upon an accumulation of new work that challenges prior scholarship. Mortimer's exploration of contemporary research has been spotty, to his considerable disadvantage. His otherwise sound account of the considerations that led to Wallenstein's murder would have profited from consulting more recent materials. Thomas Winkelbauer's Fürst und Fürstendiener. Gundaker von Liechtenstein, ein österreichischer Aristokrat des konfessionellen Zeitalters (Vienna, 1999, 224–25) has an extended excerpt from Liechtenstein's to-kill or not-to-kill Wallenstein memorandum of 1634 that gives a more nuanced picture of the thinking that preceded the assassination than Mortimer's equivalent allows. It also raises questions about Mortimer's translation of the document and the sources with which he was working. These, however, cannot be answered because the citation lacks attribution, a problem that appears in a couple of Mortimer's other longer direct quotations as well.

Mortimer's heaviest criticism targets the speculation that has often substituted for hard data in studies of Wallenstein's life and career. A notable example has been the influence on the future general of the horoscope Johann Kepler cast for him in 1608. Mortimer argues convincingly that the document played a minor role in Wallenstein's vision of himself, let alone his strategic thinking. Unfortunately for Mortimer's larger case, however, he often resorts to probabilities himself, especially when filling in the many gaps that mark Wallenstein's early life.

Nevertheless, for all of these distractions and drawbacks, Mortimer's study has much to recommend it. He can turn out gripping historical narrative when needed. His account of the plotting and execution of Wallenstein's murder moves readers along the page swiftly. He also develops a very plausible and unenigmatic take on Wallenstein's character. The general turns out to be an intelligent, canny, intellectually versatile, and emotionally quite normal man, much in the mold of the several noble military careerists (Mortimer does not like the word) of his time. Where warfare is concerned, Mortimer writes with authority and sensitivity. His insights into army life for both generals and common soldiers in the seventeenth century are well worth reading. His analysis of Wallenstein's preference to use war to force negotiated peace rather than to destroy an enemy adds new stature to his subject. He should, however, have avoided noting that Prince Eugene of Savoy admired his earlier colleague. At the battle of Zenta in 1697, Eugene's forces killed roughly 20,000 Ottoman solders in combat and drove 10,000 more to death by drowning as they tried to cross the Tisza River to safety. The episode decimated the Ottoman army; it also hastened a major peace between the sides in 1699. Not quite the technique that Wallenstein recommended.