Protecting the Roman Empire, a revised and expanded version of Symonds’s 2008 Oxford D.Phil. thesis, seeks to add to the debates surrounding Roman imperial frontiers and provincial security by focusing on the networks of fortlets (also known as praesidia or milecastles) and towers (turrets or burgi), collectively called “outposts” by him, in northwest Europe (modern Britain, the Netherlands, Germany, France, and Switzerland) in the first to fourth centuries CE. Within this scope, Symonds argues that freestanding and frontier outposts were critical in consolidating Roman control of communities and borders and in counteracting small-scale security threats, such as bandits, insurgents, or raiders. Basing his analysis largely on the placement of fortlets and towers on roads, rivers, coastlines, and linear frontiers, Symonds also uses documents from praesidia on the roads of the Eastern Desert of Egypt to “flesh out the archaeological evidence elsewhere” (182), thereby providing additional insight into the everyday struggles of soldiers in the Roman military to establish security. Symonds’s book attempts to shift the conversation back to what he considers was the fundamental purpose of outposts rather than exploring the economic, social, or cultural dynamics of the frontiers. Where his book stands out is its much-needed focus on fortlets, an often overlooked structure crucial to Roman control on frontiers and within newly conquered provinces.