Clark's approach is a mix of narrative history and background, with nicely chunked thematic subsections within chronological chapters making for easy reading. The narrative covers diplomatic and military events, but is not continuous — it leaps from the battle of Leipzig to Waterloo, for example. Instead Clark organises his account around key events. Frederick the Great's 1740 decision to annex Silesia, for example, was a pivot around which the diplomacy of the following decades revolved. The shock of the 1806 defeats at Jena and Auerstadt led to many changes, including the use of Landwehr and "free corps" volunteers and a rise in the importance of popular opinion. And there were recurring themes, such as Prussia's geopolitical weakness and the need for a foreign policy that balanced neutrality with commitment, conflicts between fathers and sons, and stresses between Prussia's component regions and with a broader Germany. The central unifying thread remains the state.
There is no attempt at a comprehensive social or economic history — which would be better handled in any case at either smaller scales or larger ones — but topics such as towns, the landed nobility, peasants and landlords, gender, industry, religious conflicts and the Jewish Enlightenment are all covered. There is also consideration of the role of historiography and historical awareness, of the way "the story of the Prussian state is also the story of the story of the Prussian state".
Clark has a magisterial grasp of his subject and adroitly mixes detail and incident with broader argument and analysis. And Iron Kingdom offers plenty of variety while remaining focused enough to maintain momentum.