The inventive political thinking of the Carolingian age, though widely recognised by scholarship on the period, remains neglected in many broader accounts of intellectual development. Yet, as Jörg Busch's study indicates, attention to the language of Carolingian political discourse has much to reveal not only about the character of contemporary politics but the evolution of western political thought in the transition from late antiquity to the Middle Ages. This study offers a thematic analysis of the use of the term ‘administratio’ and related vocabulary, tracing its development from the language of office-holding of the Roman state, reflected in late Roman legal texts, to its subsequent appropriation by Carolingian intellectuals under Louis the Pious, where it enjoyed a seemingly brief but intensive flowering in association with new, Frankish structures of delegated royal office-holding. Busch's approach is especially helpful in exploring the deeper contexts for this Carolingian deployment. Though the term was briefly applied to Clovis in the late fifth century, its use was increasingly rare in Merovingian political discourse. Administratio and its Roman resonances were known to the Franks, however, through abbreviated versions of the Breviary of Alaric and associated legal texts. Significantly, Carolingian reuse of the term shows strong associations with regions of greater structural survival from the Roman period, initially Italy, through the writings of Paul the Deacon, and latterly Aquitaine, which Louis the Pious had held as a subkingdom under his father, and from which he drew a number of his leading ecclesiastical advisers. Though the importance of such individuals has long been recognised, a major theme is the isolating of the particular contribution of two Aquitanians – Helisachar, Louis's archchancellor, and Jonas, bishop of Orléans – to the intensive redeployment of administratio, and to the construction of a broader framework of delegated office-holding and humble Christian service which is characteristic of Louis's rule in the 820s and early 830s. A particular feature of this discourse, distinguishing it fundamentally from Roman use of administratio, was the term's association with a specifically royal ministerium, placing the ruler himself in direct service to God. Yet, Busch argues, the concept of administratio fell short of full acceptance in wider Frankish usage, showing a marked decline in later ninth-century sources, whereas the language of a Christian res publica remained more resilient. Einhard's Life of Charlemagne is advanced to suggest Carolingian unease with the attribution of administratio to a ruler as opposed to his subordinates (a view partly dependent on the acceptance of a later date for the text's composition, before 828). The ultimate failure of administratio is taken to reflect the dominance of personal relationships within Carolingian practice and thinking, hindering the emergence of fully objectivised norms. Overall, this is an intricate and thoroughly researched argument which offers important perspectives on Carolingian ideas. At times it appears to rely on an opposition between lordly service and office-holding, the practical and ideological structures of which might suggest greater harmony. The role of Ansegisus' capitulary collection as a conduit for the transmission of Louis's capitularies has a further bearing on later West Frankish ideology. Such queries, however, reflect the richness and wide-ranging scope of Busch's analysis. His book deserves to be essential reading for early medievalists and all those interested in the formation of medieval political ideas.