Ferdinand Ernst was born in 1608 as the second surviving son born to Archduke Ferdinand of Inner Austria and his wife, Maria Anna of Bavaria. He was not initially groomed for leadership, but with the death in 1619 of the childless Holy Roman Emperor Matthias, which propelled his father onto the imperial throne as Ferdinand II, and the death that same year of Ferdinand Ernst's elder brother, he suddenly became the Habsburg heir apparent. After his father died in 1637, he was crowned as Ferdinand III and would then find limited success in steering both empire and dynasty through the final decade of the tumultuous Thirty Years War (1618–1648).

Histories of the Thirty Years War have traditionally emphasized the period up to the 1635 Peace of Prague, leaving the war's later years and the subsequent implementation of the Peace of Westphalia relatively understudied. Ferdinand III has similarly escaped the kind of attention given to other seventeenth-century rulers, or other Habsburg emperors for that matter. Both of these failures have recently begun to be addressed, with the publication of numerous works that more fully consider the war's latter half, as well as the appearance of not one, but two scholarly studies of Ferdinand III: Lothar Höbelt's somewhat idiosyncratic 2008 biography and Mark Hengerer's Kaiser Ferdinand III (1608–1657). Eine Biographie (2012). The current volume is an English translation of the latter work, albeit in an abbreviated form.

Where Höbelt was uninterested in Ferdinand the man, emphasizing instead the era's politics and warfare, Hengerer digs deep into archival sources to provide an in-depth study of Ferdinand's personality and the daily life at court. We gain a rich picture of Ferdinand's childhood (including such gems as the future emperor's old schoolwork), but also learn about his intellectual pursuits, physical health and enjoyments, fondness for the theatricality of Burgundian court rituals, and love of music—though unfortunately this English-language edition cuts out some lengthy sections on music that appeared in the German version (which included a CD). Throughout this work, Ferdinand is shown at the center of a web of personal relationships and appears as a family man, loving and attentive to his wives and children, dutiful to his father, and ever-mindful of his dynastic obligations.

Although the book is most valuable for its illumination of Ferdinand's personal and court life, it does not ignore the war or the era's complex political and diplomatic circumstances. Yet because it does not adhere to a strictly chronological structure, this work cannot provide a coherent narrative of the war or its aftermath, and even those deeply knowledgeable about the pattern of events may find themselves confused or perplexed by an occasionally jumbled timeline. Some parts of the discussion, moreover, such as the explanation of the causes of the war, analysis of Bohemian politics, or portrayal of French, Swedish, and Ottoman foreign policy, are overly simplistic. Nevertheless, Hengerer's book offers some valuable insights by highlighting the extent to which Ferdinand's foreign policy and diplomacy were shaped by his personality and relationships, especially those with his closest confidants at court, but also with the Spanish Habsburgs and the Bavarians, as well as other imperial nobles.

Ferdinand's relationship with the church is key as well, and he appears here as an intensively pious man, but one who, eager for peace, was often frustrated by papal machinations and more willing to compromise on religion than one might have expected. The thematic chapter on warfare is also of interest, as Hengerer blames Ferdinand's military failures on internal divisions within his army and among the imperial princes, but also on his poor strategic decisions and inability to understand the very nature of seventeenth-century warfare. In this regard, and in many other places in the book, Ferdinand comes across as a man who was cautious and aware of political realities at certain times, yet clueless, confused, and even inept at others. We see councillors afraid to give him honest advice, negotiators exceeding their orders, and generals, nobles, and allies backbiting and plotting constantly.

In sum, this is a valuable work, and one that offers English-language readers a fascinating portrait of a complex, imperfect, and yet intensely powerful man struggling to satisfy the sometimes conflicting requirements of his role as head of both an empire and a dynasty. The translation is adequate, if not always smooth, but those who are able to read the original German edition should do so, mostly to have access to its additional content (including a brief conclusion), but also because the notes in this edition are a horror. Not only do many notes refer back to paragraphs within the German edition, but all archival bibliographic information is missing and numerous abbreviations are left unexplained. For the notes to be at all usable, one will thus need to refer simultaneously to the German edition, links to which can be found in the introduction (readers should use the University of Munich link because the publisher's link is inoperative).