Military Presence and Civic Integration in Hispania Ulterior from Sertorius to Caesar offers an interdisciplinary reassessment of Roman activity in the southern Iberian Peninsula during the 1st century BC. The book integrates archaeological, epigraphic, numismatic, and literary evidence to illuminate the complex interplay between military conflict, social transformation, and processes of civic integration in Hispania Ulterior. Covering the period framed by the wars of Sertorius and Caesar, and situated within the broader struggles between populares and optimates, the volume examines how Roman armies and provincial communities—both Hispanian and Italic—shaped one another through coexistence, violence, adaptation, and cultural interaction. By analysing the role of the western provinces as providers of manpower, resources, and strategic enclaves, the studies collected here contribute to ongoing debates on the Roman war economy and the evolving nature of provincial participation in Republican military structures. The three-part structure reflects the thematic breadth of the book. The first section investigates the military conflicts of Hispania Ulterior from the early stages of Roman expansion to the Caesarian–Pompeian civil war, highlighting the involvement of local communities, the mobilisation of regional resources, and the strategic importance of sites such as Cáceres el Viejo and Ulia. The second section focuses on the archaeological evidence of Roman military presence—camps, weaponry, coinage, and ceramic assemblages—revealing patterns of territorial control and the daily interactions that fostered cultural exchange. The final section analyses the legal and civic integration of provincial populations, tracing how colonial towns, the granting of Latin rights, and the expansion of Roman citizenship contributed to the emergence of new urban, administrative, and social landscapes. These developments, exemplified by the colonisation and municipalisation programmes of Caesar and Augustus, laid the groundwork for the consolidation of the Hispanian provinces under the Principate. By emphasising the active role of provincial communities and challenging traditional narratives of unilateral Roman domination, Military Presence and Civic Integration in Hispania Ulterior from Sertorius to Caesar provides a nuanced understanding of Romanisation as a dynamic and multifaceted process. It presents the 1st century BC not merely as a period of civil war but as a transformative era in which new forms of identity, loyalty, and civic belonging emerged, reshaping the trajectory of Hispania within the Roman world.