How the Spanish Empire Was Built is essentially a book about the infrastructure of empire over the course of 400 years of Spain’s imperial presence across the globe. It is not, however, a mere erudite account of the major infrastructure projects carried out by Spain across its global possessions, nor is it a collective biography of the engineers who designed and built the empire’s infrastructure. Rather, it is an attempt to use the study of imperial infrastructure “as the scaffolding, as it were, on which the empire was erected” (30).

Taken on its own, the previous statement seems a bit cryptic. To bring the argument into sharper relief, we must first understand the historical question that drives the book. Although never explicitly stated, the goal is to explain the Spanish Empire’s long life of over 400 years. The resilience of the empire is especially surprising considering that, despite our proclivity to project strength onto the Spanish crown, the Spanish Empire was quite weak for most of its history. How could such a weak empire last so long?

Here, the authors—two esteemed and erudite historians of the Spanish Empire—highlight the importance of infrastructure. In fact, without ever expressing it in a direct way, Felipe Fernández-Armesto and Manuel Lucena Giraldo are convinced that the effectiveness of Spain’s imperial infrastructure explains, in large part, the longevity of a militarily and politically weak empire across large swaths of the globe—a claim they defend by discussing some of the empire’s main infrastructural projects, from maritime routes to hospitals.

The first chapter discusses the engineers themselves, who were practical men with a disposition to solving problems as they arose, from building fortifications and government buildings to bridges and drainage systems. Many so-called engineers, some of whom were clerics and missionaries, learnt their trade on the ground in the context of political and environmental challenges. It is safe to say that many of these imperial engineers, at least before the professionalization of engineering in the nineteenth century, were adept tinkerers.

A few important chapters deal with the maritime and land routes that connected Spain’s global empire. The Spanish maritime routes across the Atlantic and Pacific were a tremendous feat, as they required deep understanding of wind currents, which developed by the accumulation of experience from Columbus onward. What is more, though often deemed economically inefficient, the convoy systems that traversed these routes were largely successful at preventing rival empires from seizing the copious amounts of bullion extracted from New World silver mines. As for land routes, the success of the Spanish Empire can be largely explained by its exceptional ability to harness Indigenous road systems.

The next chapters deal with bridges and fortifications. While Spaniards had experience with stone bridges, they were fascinated by the large suspension bridges they encountered in the New World, which were made with rope and timber. Across their global empire, Spanish used both kinds of bridges with great success. As for fortifications, these were some of the most important infrastructure projects built by Spanish engineers, especially in the frontiers, where Spanish settlements were often exposed to attacks. Topics covered in the remaining chapters include ports, shipyards, social and economic infrastructure, and hospitals.

This cursory summary cannot do justice to this erudite book, covering over 400 years of history, nor will my upcoming critical comments take away from the value of the book. That said, and in the spirit of constructive scholarly discussion, let me offer a few critical observations. My main qualm with the book is that, though countless arguments have been offered to explain the longevity of the Spanish Empire, the authors largely refrain from engaging with them.

Among the most important competing explanations, we can include historians who argue for the “stakeholder” model of the empire’s political economy, by which the state divested some of its functions to local elites to lower bureaucratic costs and cultivate loyalty. Others insist on the polycentric nature of the Spanish Monarchy, which enabled key extra-European territories to function as political centers in their own right. Still others argue for the negotiated nature of policymaking, which allowed subjects across the empire to have a say in imperial politics by way of petitions.

The authors could very well be right that infrastructure goes further in explaining the endurance of Spain’s global empire. But, without adequately exploring competing explanations, one cannot properly defend such a bold assertion. This critique aside, this is an erudite and incredibly valuable book. In addition to being stylishly written, the book contains a cornucopia of interesting and useful information, whether your purpose is to learn more about imperial infrastructure or prepare an undergraduate lecture. Without a doubt, I will keep coming back to this book for years to come.