How, exactly, did Rome become master of the ancient world? This book examines and illustrates the tactics employed by the legions of late Republican and early Imperial Rome, from the evidence o f ancient writers. The greatest military machine in the Western world for at least four centuries, the Roman Army was the foundation of the Western military tradition, and its doctrines were central to the later revival of trained, drilled professional armies. Here the evidence is discussed in clear detail, and brought to life with battle plans and full colour interpretations of tactical scenarios.