The American Presbyterian Church was committed at its inception to the belief that it is a missionary church and that every member is a missionary. The establishment in 1837 of the Presbyterian Church’s Board of Foreign Missions signaled the beginning of a worldwide missionary operation destined to embrace some fifteen countries in four different continents. The records offered here provide invaluable information on social conditions in Persia (renamed Iran in 1935) and on efforts to spread the gospel during the nineteenth century. Documenting the church’s educational, evangelical, and medical work, these are records mainly of incoming correspondence from the mission field and outgoing correspondence from the Board headquarters.