Since its founding a century ago, the IRM has sought to advance learning about mission strategy, methods of evangelization and mission theology. How the journal has affected the development of the field of missiology is the particular focus here, through a survey of exceptional articles. Three phases are identified: a first period when the journal closely reflected the outlook of the World Missionary Conference (Edinburgh 1910), but also began to innovate; a middle period of transitions; and the more recent period when issues of interfaith dialogue, religious pluralism, contextualization, and ecumenical relations have been prominent in the journal.