How is Christianity to express itself in the public forum within Western nations? This book seeks answers through a historical retrieval of the dynamic mission in post-war Scotland of Tom Allan and his contemporaries: the Iona Community; the Gorbals Group Ministry inspired by the East Harlem Protestant Parish; and Robert Mackie, Ian Fraser and Scottish Churches House. Allan's missiology focused upon the apostolate of the laity: allowing ordinary people to express their faith in word and deed in a full contextualization of Christianity to seek a missionary parish of constant witness and service. The book examines his work in parish ministry, nationally as leader of the Tell Scotland Movement, and internationally with the WCC; and the rich sources and context of his missiology. Key questions are asked about tensions caused by the role of the church, and the effect of the Billy Graham "All Scotland Crusade," which Allan instigated, on the rapid decline in Christian adherence from the late fifties. His work is placed alongside his contemporaries, who took bold steps beyond those of Allan to relocate faith to the rhythms of the streets. Utilizing present day missiology as a lens, their inspiration leads to derivations and principles, offered as guideposts for Christian mission now.