My first city was Conan Doyle’s London, in the company of Holmes and Watson. My mother gave me a two-volume omnibus edition when I was 10. London was a vast, cozy, populous mechanism, a com­forting clockwork. Foreigners and criminals served as spices, highlighting the assumed orderliness and safety of the Empire’s capital (assuming one were sufficiently comfortably placed in society, and in Doyle one tended to be).