This introduction presents an overview of the key concepts discussed in the subsequent chapters of this book. The book explores the applicability of the military revolution (MR) concept to Portugal and to its empire during the early modern period. It explores the renovation of the fortress of Azemmour (Morocco) during the first half of sixteenth century from a cross-disciplinary perspective. The book argues that change and readaptation in Portuguese African overseas outposts was following the theoretical precept circulating in Europe. It deals with the Portuguese experience regarding early modern fortification, its connection with the education of engineers, and the dissemination of knowledge. The book explores topics such as what resources the state allocated to war and how relevant the major stakeholders actually were to warfare in the long run. It examines whether there was an MR at all in Portugal in the early modern period.