Evidence for Oxfordshire’s strategic location in ancient times can be found in the remains of prehistoric hillforts, fortified Roman towns and Saxon burhs. Both Oxford and Wallingford were besieged during Stephen and Matilda’s war of succession and again 500 years later during the Civil War. Charles I chose Oxford as his capital, defending it with garrisons at Bletchingdon, Banbury and Chipping Norton. Later, local volunteer forces formed in the county, gaining state recognition during Queen Victoria’s reign and bolstering regular regiments in the two world wars. In the Second World War, Oxfordshire’s River Thames was a critical component in anti-invasion defences, and the county’s air bases provided the means for the RAF and USAAF to launch bombing raids into Nazi Germany. Lastly, since before the Cold War, the villages of Harwell and Culham have been contributing to Britain’s development as a nuclear power. Defending Oxfordshire delves deep into the county’s military landscape, revealing a unique and fascinating perspective of its history. Dr Mike Osborne’s interest in fortification began with childhood visits to castles, and has developed over the years to include all aspects of the topic, from Iron-Age forts to Cold War bunkers. He was a volunteer-coordinator for the Defence of Britain Project, recording the military structures of the twentieth-century, and, after a thirty-year-career in education, took early retirement. Since then, he has produced nearly twenty books on topics that range from Civil War sieges and fortifications, to drill halls and twentieth-century military structures. He has also written a series of county surveys of defences, as well as the best-selling Defending Britain.