This chapter identifies the first 27 Londoners to live in a Sunnyside, from 1859-1872, after which the name increased rapidly. Their biographies are given, and the methods used are identification of social networks and communities of practice. Religious nonconformism turned out to be key, as the first four London Sunnysiders were a Swedenborgian, a Sandemanian, a Plymouth Brother, and an unidentified dissenter married to a Wesleyan Methodist. Early London Sunnysiders were wealthy, successful, socially-embedded businessmen, owning their own companies and employing others. The earliest London Sunnysiders had overlapping social networks via their professions (the paper and print industries), their livery companies, their charitable activities, their Nonconformist churches, and family ties. They had a raised likelihood of Scottishness, either by descent or by connection. Early London Sunnysides were large detached suburban houses, newly-built, near to railway-stations.