The lectures on which this publication is based weredelivered as the Rhind Lectures to the Society of Antiquaries of Scotland inMay 2019. The annual Rhind Lectures commemorate Alexander Henry Rhind(1833-1863), a Fellow of the Society renowned for his excavations (finds fromwhich are now in the National Museum of Scotland) and publications. The 2019lectures were generously sponsored by AOC Archaeology Group.The first two lectures - chapters in this book - provide thehistoriographical background to our present understanding of Hadrian's Wall. They start with John Collingwood Bruce, the leading authority on the Wall, from1848 until his death in 1892, who gave the Rhind lectures in 1883 and whoseinfluence continues to this day. Research on the Wall in the field and in thestudy from 1892 to the present day are covered in the second lecture. The thirdand fourth lectures consider the purpose(s) and operation of Hadrian's Wallfrom the first plan drawn up soon after Hadrian became emperor in 117 throughto the final days of its existence as a frontier shortly after 400. Fivedistinct 'plans' for the Wall are promulgated. The fifth lecture examines theimpact of the frontier on the people living in its shadow and beyond. The lastlecture reviews the processes which have brought us to an understanding ofHadrian's Wall and considers the value of research strategies, with somesuggestions for the way forward. The chapters in this book reflect closely thelectures themselves with the main change being the addition of references.