There have only been a few scattered attempts to go into any detail about the command structures employed by the Templars and Hospitallers. Consequently, Jochen Burgtorf's monograph on this subject is an extremely welcome addition to current historiography. His work is divided into three sections which look at the history of these orders' central convents, their conventual organisation and the careers of their leading personnel. The first section primarily details the way in which organisational structures evolved in both orders to accommodate their growing power and responsibility. Like all areas of the book, this constitutional history is authoritative and effectively explores the influence of each order on the other's development. It also discusses the role of the princely court as a template for the Templars and Hospitallers' leadership structures. This ‘vertical’ analysis of the orders' chronological development is particularly valuable because so many previous studies have focused primarily on giving a ‘horizontal’ snapshot of an order's establishment in any one time. The second section is more familiar, working through the equipment, titles, functions and role of each individual officer. Its great contribution lies in the depth of its analysis. In addition to utilising the available sources in a qualitative fashion, Burgtorf has also looked for ways in which the available material can be quantified and/or tabulated. This approach is not new, but it has been taken to an advanced level and this has allowed him to revise old assumptions and draw new conclusions. The strength of these two sections lies in the precision and clarity with which they cut through a number of grey areas in the constitutional history of these orders, including matters such as the resignation of Master Gilbert of Assaily and the status of the Hospitallers' fortress at Margat. The third section is concerned primarily with a prosopographical analysis of the leading brethren. It looks at the careers and origins of a number of major office-holders, drawing comparisons and identifying patterns in career path and origins. This is followed by perhaps the most important element in the book, a prosopographical register of the conventual officers of both orders. This register supplies evidence for the earlier sections, but more important it provides a valuable resource for future research. Indeed, in general, although the book reaches important conclusions on its own account, its significance lies more in its role both as a platform for future research and as an exponent of quantitative methods in the study of the military orders.