On Hadrian’s vision for the Roman empire, see Jocelyn M.C. Toynbee, The Hadrianic School: A Chapter in the History of Greek Art (Cambridge: Cambridge Univ. Press, 1934), still one of the best books on Hadrian. Another “best book,” of a very different kind, is Marguerite Yourcenar’s brilliant Memoirs of Hadrian, trans. Grace Frick (New York: Farrar, Straus & Giroux, 1954), a fictional autobiography based on the ancient sources.